363

ШЫР SOME AUSTRALIAN TERMITES ОЕ THE GENERA DREPANOTERMES, HAMITERMES AND LEUCOTERMES.

Bs GERALD ae HIET ERES. (Plates IX-XII.)

This paper is intended as the first of a series in which it is proposed to record the results of an examination of a large collection of termites from various parts of the Australian continent. The greater part of this collection has been gathered in the northern districts of the Northern Territory, and in North Qucensland, but during the past vear it has been considerably increased by the addition of numerous small collections received from correspondents in Victoria, Western Australia and South Queensland, and now contains individuals from over 800 colonies. Through the courtesy of the authorities of the South Australian Museum I have been able to examine a number of co-type specimens which have been of the greatest assistance in clearing up many doubtful identifications. 1n addition to these, I have been able to study many species from localities not represented in my own collection.

For various reasons it has not been found practicable to study the species contained in these collections in systematic order; in many instances imagines, which are sometimes essential to satisfactory determination of species, are wanting; in others, reference to types or authenticated specimens of previouslv described species is necessary in order to obviate the possibility of creating synonymy. It is proposed, therefore, to deal with the various species more or less at random, leaving the pre- paration of a more comprehensive work until such time as our knowledge of the Australian termite fauna is much more complete than it is now.

Dr. Eric Mjóberg (1920) has recently added no less than 36 new species to those previously known from Australia and New Zealand, and has otherwise much increased our knowledge of the order. He lists 80 species, exclusive of some which have been too imperfectly described for identification, as comprising the termite fauna of Australia, Tasmania and New Zealand. To this list, however, should be added two old described species, viz., Calotermes convexus, Walker, and C. obscurus, Walker, the types of which are still in existence, Levicofermes paradoxus, l'rogg., and eight Northern Territory species described by me in 1915.

Eight new species, one new variety, and one hitherto unknown imago are described in the present paper, leaving at least 20 new species in the writer’s collection to be dealt with. In addition to the latter number there are several species which cannot be satisfactórily described until more complete material is available for study.

A critical examination of a large collection of Hamitermes, Drepanotermes, Leuco- termes, Rhinotermes and Coptotermes, has shown conclusively that in many species determinations cannot be made satisfactorily, if at all, from the soldier and worker castes alone. This fact will be made clear in this and subsequent papers.

Although aware of Fuller's recent paper (1920) on the antennae of termites, 1 have followed recent writers on the Australian species in regarding the number and form of the joints of this organ as possessing considerable taxonomic value. While due allowance must be made for the variations which certainly do exist in the antennae of nest-series, and not infrequently in the antennae of individuals, I see no reason at present for departing from the general practice of referring in some detail to antennal characters in descriptions of new species.

The wing measurements recorded in this paper were taken from the humeral suture to the apex. Head lengths, excepting where otherwise stated, are from the posterior margin of the head to the apex of the mandibles. Measurements are given in millimetres.

The type series, unless the contrary is stated, are in the author’s collection.

(5296) Wt. Р.8/170 1,000 1/22 Harrow С. 75/1. 2E

364 GERALD F. HILL.

Drepanotermes silvestrii, sp. n.

Imago.—Head very dark brown, nearly black; postclypeus, thoracic, and abdominal tergites Brussels brown ; lower surface chiefly antimony yellow ; mid and hind tibiae, pleurae, and lateral blotches on abdominal sternites dark ; wings dark brown.

ee 10 Drepanotermes silvestrii, sp. n., head and prothorax of imago.

Head (fig. 1) rounded behind, flat on the summit, glabrous, moderately setose, Labrum moderately large, swollen on the sides, rounded in front. Anteclypeus, membranous, pointed in front. Postclypeus rather larger than in D. rubriceps, Frogg., twice as wide as long. Eyes small, nearly circular (0-329 x 0-376), slightly projecting. Осе! large, oval, oblique, well separated from the eyes, anterior margin in line with anterior margin of eyes. А small deep impression on either side between the ocelli and clypeus. Fontanelle large, broadly oval, very distinctly visible, with small indistinct forward extension. Antennae 18-jointed, not variable in size and shape of segments ; 1st joint long, stout, cylindrical, more than twice as long as wide; 2nd three-fifths the length and two-thirds the width of Ist; 3rd and 4th very short, shortest of all, narrower than 2nd, coalesced; 5th short but distinctly longer and wider than 3rd and 4th; 6th longer and wider than 5th ; 7th, Sth and 9th equal; 10th longer than 9th; 11th to 15th about equal; 16th and 17th a little longer and narrower, 17th narrower than 11th to 16th; 18th as wide as, but longer than 17th, as long as Ist, pointed.

Fig, 2. Drepanotermes silvestrii, sp. n., hind tarsus of imago.

Prothorax (fig. 1) nearly flat, slightly sinuate and bent up in front, antero-lateral angles rounded, sides rounded to the rounded posterior margin, moderately setose. Meso- and metathorax uniform brown, wing-stumps similar to those of D. rubriceps but smaller. Legs (fig. 2) very long and slender, armature alike in each excepting that the first tibiae bear the usual additional spur ; fourth tarsal of each leg very long and slender; femora all about equally stout.

ON SOME AUSTRALIAN TERMITES. 365

Wings (fig. 3) with the margin ciliate, membrane with very few hairs; dark brown, a little lighter on costal border; subcosta very short, hardly extending beyond suture; costa and radius well separated, the latter very dark, joining the former near the apex, sometimes giving off beyond the middle numerous small veinlets to the costa; median of the fore-wing branching from the radius within the wing- stump, moderately thick at the base, nearer to the cubitus than to the radius, branching very irregularly, sometimes dividing into two before the middle and each branching again into two or three, the main superior branch joining the radius near the distal end of the latter or bending downwards and joining the wing margin at or very near the apex, if the former, a number of small cells are formed beyond the junction ; sometimes the branches are all curved downwards and reach the hind margin below the apex. There is always a network of veinlets between the median and radius. The median vein of hind-wing branches from the radius beyond the suture, but otherwise it is like that of the fore-wing ; sometimes there is an inferior branch near the base which joins the cubitus about the proximal third of the wing ; some- times this branch joins the second one and forms a large elongate cell, or there may be a succession of cells of varying shape and size. The cubitus of the fore-wing has from 10 to 16 branches, forked or simple, alt of which join the hind margin before the distal fourth or fifth of the wing: that of the hind wing has from seven to nine simple or forked branches, the first five to seven of which are much darker than the others.

Fig. 3. Drepanotermes silvestrii, sp. n., wings of imago.

Abdomen large, distended, with eight distinct broad dark tergites, clothed with short fine hairs, and with apical and lateral margins fringed with longer yellow hairs. Ventral surface of female with six visible yellow-ochre sternites, each with dark lateral blotches, the fifth longer than the preceding ones, but much shorter than the sixth. The male has eight distinct sternites, the fifth and sixth longest, the seventh much shorter and narrower, the eighth shortest and very narrow. Cerci short and stout. Styli absent in both sexes.

Measurements* : Length with wiugs, 19-20; length without wings, 11; head, with mandibles, 2-16 long ; head, at and including eyes, 1:7 wide; antennae, 3; mandibles, right,0-92-1-031ong, 0- 7-0: 75 wide; left, 1 -03-1 -08 long, 0 -62-0 -65 wide ; prothorax, 0-94 long, 1-64-1:78 wide; forewings, 15-16 long, 4 wide; hindwings, 14-5long, 4:5 wide ; tibia (i) 1-42, (п) 1-55, (iii) 2-11; abdomen, 2-75 wide.

* Given in millimetres, 5296 2Eo

366 GERALD F. HILL.

Queen.—Antennae generally complete, 7.e., 18-jointed ; wing-stumps often muti- lated; two or three legs generally amputated, claws of remaining legs short and blunt, apices of second and third tarsi heavily chitinised. Eight dorsal and six ventral abdominal plates distinct; pleurae and integument cream-coloured. Abdomen 16 long by 6 wide. Other characters as in imago.

King.—Uniformly dark above; abdomen much contracted and plates over lapping ; pleurae obscured bv dorsal and ventral plates. Other characters as in queen and imago. One specimen examined ; apparentlv very old ; associated with two old neoteinic queens.

Neotetnic Queen.—Head and clypeus yellow-ochre, prothorax a little lighter ; tergites and sternites amber-yellow, the latter with wearing surfaces dark and heavily chitinised, pleurae and spaces between plates cream-coloured. Head wide; eyes small, hardly projecting, only inner facets pigmented; ocelli as in imago ; fontanelle a large oval cavity about as large as and shaped like eye (in nymphs of the first form itis much smaller and proportionately more elongate, as in adult) ; antennae 17-jointed, apparently never mutilated, third and fourth joints fused, short; pro- thorax shaped as in imago ; wing-buds long, slender, subequal, three-fifths length of the entire sclerite. Abdomen with cuticle horizontally striate.

Measuremenis: Head, at and including eyes, 1:70 wide; prothorax, 0-94 long, 1:60 wide.

Described from two old individuals found in association with the true king des- cribed on a preceding page. Several other similar specimens seen. These forms are derived from nymphs of the second form, t.e., in the stage preceding the acquisition of the long wing-buds characterising nymphs of the first form, t.e., those which аге destined to develop into winged imagines. In second form nymphs, and neoteinic queens developed from them, the mesonotum and metanotum, including wing-buds, measure 2-35 in length; in nymphs of the first form, t.e., potential winged imagines and true kings and queens, the length is 4:25. The antenna in each is 17-jointed.

Fig.4. Drepanotermes silvestrii, sp. n., head of soldier.

Soldier. —Head orange-rufous to Sandford’s brown; mandibles mahogany-red ; labrum yellowish, apex hyaline; antennae nearly as dark as head; junction of segments hyaline ; pro-, meso- and metathorax russet to argus brown; legs and abdominal tergites light clay-colour.

| |

ON SOME AUSTRALIAN TERMITES. 367

Head (fig. 4) very large and broad, rounded behind, with a pale median suture from posterior margin forwards, widest behind the middle, sloping in towards the antennae, bearing a few moderately long reddish hairs, variable in size. Mandibles very long, falciform, each with a large angular tooth before the middle (fig. 5). Labrum large, wide at the base, sloping on the sides to the bluntly pointed apex. Clypeus three times as wide as long, divided into two lobes by a deep and wide median cleft, which extends posteriorly into the front of the head. Antennae 17- or 18-jointed, generally segmented as in D. rubriceps, Frogg., sometimes third and fourth joints closely fused and together only equal to sixth in length.

Prothorax (fig. 4) much narrower than head, anterior half rounded and bent up in front, slightlv emarginate in middle, postero-lateral angles rounded, hind margin rounded and slightly emarginate in middle; the margin clothed with short stout reddish hairs. Mesothorax narrower and shorter than prothorax, hind margin with a few stout reddish hairs. Metathorax as wide as prothorax and clothed like meso- thorax. Legs very long and slender, with scattered reddish hairs, fourth tarsal very long. Tibial spurs 3: 2: 2, asin other Drepanotermes and Hamitermes.

Abdomen elongate, narrow, with scattered stout reddish hairs and a few siender golden ones оп tergites and sternites. Cerci long and slender. Styli present or absent.

^

Fig. 5. Drepanotermes silvestrii, sp. n., base of jaws, labrum and clypeus of soldier.

Measurements: Total length, 6:25-7; head and mandibles, 2:75-3:1 long; thorax and abdomen, 4-4-5 long; mandibles, 1:31—1:64 long; head, 1-6 wide; 1:25-1:35 deep; antennae, 3-29-3-61; prothorax, 0-51-0-56 long, 1-03-1-12 wide ; tibia (i) 1-5, (ii) 1-5, (iii) 2-11-2-39 ; abdomen, 1:5 wide.

Worker.—Colour of head as in soldier, or a little darker, with pale median suture extending forwards from the posterior margin, widening behind the fontanelle and spreading out behind the frons ; clypeus clav-colour, labrum yellow-ochre ; antennae a little paler; rest of insect clay-colour ; prothorax a little darker than terzites and legs. Immature workers and soldiers have body and legs tinged with rose pink.

Head large, rounded on the sides and behind, nearly as wide as long, widest behind the base of the mandibles. Labrum large, convex, swollen on the sides, rounded in front. Anteclypeus membranous, short, pointed. Postclvpeus large, convex at base, not quite as long as wide, sides rounded, anterior margin truncate. Antennae very long, 18-jointed, arising within a deep cleft situated well in from sides of head. Fontanelle as in imago.

Prothorax as in soldier, more setose, much narrower than head. Legs long and slender, clothed with scattered reddish hairs. Tibial Spurs 2: 2: 2.

Abdomen elongate oval, hairs more numerous and more slender than in soldier. Cerci long and slender.

Measurements: Total length, 7-7:5; head, with mandibles, 2:16-2:35 long ; thorax and abdomen, 5:5 long; head, 1-93 wide; antennae, 3-61 ; prothorax, 0-56- 0-біоле, 1-22 wide ; mandibles, left, 0-97 long, 0-65 wide, right, 0-86 long, 0-77 wide.

368 GERALD F. HILL.

Biology.

This is one of the three predominant species of mound-building termites that are found in the Townsville district, N. Queensland. It inhabits the same localities as H. perplexus, sp. n., and the termitaria of the two species are often found in close proximity, although those of the latter are rather more common, especially on hill- sides. On the higher and stony localities many large colonies live entirely in under- ground galleries, the extent and nature of which have not yet been investigated sufficiently to determine whether they are connected with large masses of cells and passages comparable with termitaria. This seems most probable, since it is known that these colonies collect and store considerable quantities of food, and that eggs, young larvae and the reproductive forms are not found in the galleries near the surface, which serve apparently only for the accommodation of workers and soldiers, and a few adolescents of these castes, and for the temporary storage of food material during and just after harvesting operations. Ав all the normal castes are reared by these colonies, it seems reasonable to assume that each is provided with an under- ground system suitable for the location of the royal pair and their young and for the storage of food. On the other hand, considerable excavating failed to disclose a regular nest ог“ nursery " in the closely allied species D. septentrionalis, sp. n., in the Northern Territorv (Hill, 1915). In the case of D. septentrionalis, small foraging parties of soldiers and workers are commonly found in the termitaria of Coptotermes and Eutermes, but this is not the case with D. silvestrit. Access to the surface 15 gained by means of numerous small oval openings, from 18 in. to 8 ft. apart, and extending over an area of from 6 ft. to 12 ft. in diameter. These openings measure about З mm. long by 6 mm., and except when actually in use, 7.6., at harvesting or “swarming " periods, are sealed with earthy matter, either level with the surface or just below it, in either case rendering their detection very difficult. Similar surface openings are found in the vicinity of termitaria, when these are constructed; but they appear to be used solely at harvest time—certainly not to provide a means of exit for the winged forms at the time of swarming. The natural dispersal of the imagines has not been observed, and it is not known whether the phenomenon occurs during daylight or at night. A day or two before swarming takes place, slits are cut in the walls of the termitarium, generally in several places near the outer margin and several inches above ground level. These slits are sealed over by a projecting crust of moist earthy matter, as in H. perplexus, sp. n., and remain thus until weather conditions are favourable for the flight, after which they are cemented up flush with the general surface of the walls.

One of the most remarkable habits observed in this species, and also in D. septen- trionalis, is that of gathering food supplies by day as well as by night. Froggatt (1915) observes that travellers in the bush, who have gathered a mass of dried grass upon which to make their temporary bed, have been aroused to find hordes of termites (species not stated) cutting the material into lengths and removing it for food. Such is by no means a rare experience in North Australia, and it occurs during the day as well as at night, D. septentrionalis being the species concerned in all cases which have come under my notice. In this district I have frequently seen countless thousands of soldiers and workers of D. silvestri? issuing from several holes in the surface and spreading out in irregular columns over an area of several yards, each worker cutting off a length of grass (leaf or stem), a piece of eucalyptus leaf or twig, or seizing a seed or small piece of bark and hurrying back along the column to one of the openings, at each of which there is a good deal of congestion, but no sign of disorder or wasted effort. Throughout these operations the soldiers are much in evidence, regulating the traffic, scouting on the outskirts of the working parties, attacking marauding ants or any other insects or spiders they may encounter, and generally taking a strenuous and important part in the proceedings. Their behaviour is in marked contrast to that of their near allies the Hamitermes, and

ON SOME AUSTRALIAN TERMITES. 369

many other species, in which the soldiers appear to be the embodiment of cowardice and uselessness. Оп one occasion harvesting operations were observed at night on the roadside in one of the more populous residential areas of the town, the material gathered being almost entirely coarse dry grass, which was cut into pieces about half an inch in length. The nature of the food varies according to the scason of the year, the flora in the immediate vicinity and other circumstances. When there is a plentiful supplv of dry grass this material appears to be most favoured, but there is nearly always present a quantity of grass and other seeds and a good deal of vegetable debris. In the vicinity of eucalyptus trees they gather pieces of leaf, leaf- stems, twigs and bark. The latter are carried into the А in the rough state and afterwards dressed into pellets of varving size and shape. None of the species of this genus are wood-eaters, nor are they known to attack cultivated cereals.

Тіс termitaria are nearly always low, flat and more or less circular masses composed of intensely hard cement-like material, varying in toughness according to the soil in which they are situated. In size they vary from about 8 in. to 2 ft. in height by 2 ft. 6 in. to 8 or 9 ft. in diameter. In gross appearance they resemble a mass of soft mud which has spread over the surface and hardened by evaporation (Pl. ix, fig. 1). There is no well-defined outer casing or wall (PL ix, fig. 2) as in nests of Coptote Ymes, the whole of the superstructure being composed of similar material. The interior is occupied by very large flattened chambers connected with each other by small circular holes large enough to permit of the free passage of soldiers and workers from chamber to chamber. Similar but rather larger chambers extend below ground, under the middle of the superstructure, to a depth roughly corresponding to the height of the latter. These chambers are excavated in the soil, and are much less resistant to digging operations than those above ground. Below them are several passages extending more or less vertically into the soil beneath. The majority of the chambers in the superstructure are occupied by workers, soldiers, and older adolescents, and by masses of grass and other foodstuffs. The latter is generally stored in the rather smaller outer cells, many groups of which are reserved for the reception of the waste matter from the community, t.e., alimentary rejectamenta and the heads of dead soldiers. Evidently much of the waste material is carried in the jaws to these chambers, where it is tightly packed until the space is entirely filled, then the small entrances are cemented up, apparently never to be reopened. Other chambers are reserved for the reception of the faecal matter of certain individnals, probably soldiers and workers, who evacuate directly into them. Such chambers, when in use, are indicated by a deposit of more or less liquid matter just within the small entrance hole, the remainder being empty. As the deposit increases and hardens the entrance becomes blocked and is then cemented up. Analyses of the rejecta- menta in these termitaria show that they contain about 32 per cent. of inorganic matter. Additions to these nests are nearly always made by extending the outer walls without increasing the height, and the increase in the diameter of the superstructure is greatly in advance of that of the underground portion. The latter is occupied bv the reproductive forms, eggs, larvae and nymphs, and by their attendant soldiers and workers.

All the different castes have been found in the same nest and at the same time, but an ovigerous neoteinic queen has not been found in a nest presided over by a true queen. The soldiers are very numerous, active and pugnacious, and are capable of a most effective fight against marauding ants. When the termitarium is broken into the soldiers rush out in all directions, attacking every animate object they come in contact with—their fellow-soldiers and workers, ants, lizards and one's hands receiving equal attention. Some few devote their energies to rescuing their defence- less larvae, but this function devolves more upon the workers, who are hardly less pugnacious. Normally the colony is presided over by one true queen, who is generally located at, or just below, ground-level in a flattened cell of rather smaller size than the average cell in these nests. In one case only has a true king been found in the

370 GERALD F. HILL.

queen cell. The true queen produces an enormous number of eggs, which are carried away by the workers and stored in masses in cells near the walls or near the queen- cell. Egg-laving is not confined to one particular season of the year, but it is not a continuous process, since eggs are often absent in certain thriving colonies while present in great numbers in others close by. Neoteinic queens are substituted for à true queen when a colony is naturally or designedly orphaned. Іп one colony a true king was found in a large cell with one ovigerous neoteinic queen ; in another there were one true king and two of these neoteinics, in a third there were two neoteinics only, and in a fourth one neoteinic king and two neoteinic queens. Neoteinic queens of this species produce neoteinic males and females, as well as soldiers, workers, and nymphs of the first and second form.

The following field notes refer to termitaria of this species which have been kept under observation for some time :—

(1) This colony was orphaned on 22nd August 1919. When examined on 15th June 1920, it contained 20 young neoteinics of both sexes. There were no eggs or very young larvae present, but there were numerous halt-grown larvae and second form nymphs. On 26th October 1920, two ovigerous neoteinic queens and four neoteinic males were removed from the nest. Eggs, voung larvae and nymphs of the second form were plentiful. Some of the latter and one young neoteinic female were left in the nest, with workers and soldiers. By 15th February 1921, the termitarium was again restored to its original size and presented a very prosperous appearance. Eggs and young larvae were present, but no gravid female could be found. There were no young neoteinics present, but the second form nymphs which were left in the nest on the 26th October had now developed into nymphs of the first form. Тһе parent of the eggs and young larvae found on this date was presumed to be the young neoteinic female left in the nest on 26th October.

(2) This nest was orphaned on 15th June 1920. Оһ 26th October 1920, it con- tained four ovigerous neoteinics and nine immature neoteinic males and females. There were present also numerous second form nymphs, besides the usual workers and soldiers. The termitarium was now completely destroyed. Оп 15th February 1921, the nest was found to have been rebuilt to its original size and to contain numerous eggs, young larvae and nymphs of the second form. There were no nymphs of the first form or imagines present and the parent of the eggs and young larvae was not found. The whole termitarium was again destroyed, and on 18th March 1921 a good deal of it was found to have been rebuilt.

Each of several other nests which were orphaned at different periods of the year were found to contain neoteinic queens when examined subsequently. It has not been ascertained if a colony once deprived of its true queen is ever again presided over by another true queen ; the contrary appears to be the case. In nests which are presided over by a true queen, or by one or more gravid neoteinics with numerous neoteinics in reserve, nymphs of the second form are found throughout the year, except- ing from the middle of December to the end of January. A moult takes place about the former period, and the resulting first form nymphs have been found as late as 13th February, but the majority undergo their final moult and appear as imagines about the beginning of January, and all have moulted before the 8th March. When true queens or mature neoteinic queens are not present, nymphs of the second form may be present throughout the year. First form nymphs have not been found later than 15th February or earlier than 5th November. The actual date of swarming is determined by rainfall. In 1919-1990 first form nvmphs were plentiful in the nests on 5th November 1919; the final moult took place between this date and 8th December, when most of the imagines were capable of flight, although some had not vet moulted. On 6th January and l5th January (1920) first form nvmphs and imagines were still present in the nests. Тһе former moulted before 30th January, and swarming took place before 10th February. In 1921 the wings of the majority

ON SOME AUSTRALIAN TERMITES. ӘЛІ!

were fully developed on 15th February, but on 8th March, up to which date only light rain fell, these forms were still present im all the nests examined. Оп this date the tips of the wings showed marked damage due to prolonged occupancy of the parent nest. Similar conditions prevailed in the nests of Hamitermes per plexus, sp.n. Heavy showers fell on the night of the 9th March and throughout the day and night of 10th. Swarming of H. perplexus took place during the afternoon and evening of the latter date. The swarming of D. silvestrii was not observed, but probably took place about the same time, since none of the nests contained imagines on 14th March.

It is not intended to discuss in detail here the numerous other forms of life which have been found in termitaria, but brief mention may be made of one species which plays an important part in the economy of two species of termites dealt with in this paper. At a very rough estimate it may be said that 80 per cent. of the termitaria of D. silvestrii and H. perplexus are invaded and permanently occupied by the very common and widely distributed ant, Iridomyrmex sanguineus, Forel, which is particularly abundant on thelow-lying country in the vicinity of Townsville. The termitaria are entered bv means of holes burrowed into the walls (Pl. xii, fig. 2), in and out of which pass endless streams of ants in their journeys from one nest to another. If a termitarium is cut open verticallv, it will be found that the ants have greatly enlarged the original galleries so as to form large tlattened chambers in tier upon tier, until finally the greater part of the structure is in their undisputed possession. The floor of each cell is thickly covered with the eggs, larvae and pupae of the invaders, and immense numbers of ants throng all parts not actually in possession of the termites. Astheants extend their sphere, the termites are driven back from chamber to chamber and destroyed, until but a few stragglers are left. The complete, or nearly complete, occupation of a termitarium is evidently a matter of time, during which the advance is being constantly delayed by the termites walling up their galleries and passages as they retreat. The remains of the dead termites in the chambers occupied by ants show clearly that the nests are not attacked merely to provide a dry and safe shelter, but that the original occupants are used as food. Immediately the walls are broken with the pick the ants swarm out in countless thousands, destroying and carrying off the dislodged termites, crawling up one's legs and attacking one's hands, head or any skin surface to which they can gain access. Others of their kind gather from all directions to take part in the onslaught, until the nest and the surrounding ground is a seething mass of insect hfe. Under these conditions a close examination of the nest or its occupants is impossible, and it is only by finding an ant-free nest that one can hope to investigate its interior. Within a few minutes of the nest being broken into all the neighbouring ant- infested termitaria of these two species will be found to contain the bodies of freshly killed termites, while files of ants pass to and fro so long as a termite remains exposed to attack. Plate xii, fig. 1, shows ant tracks made on the surface of the ground approaching a mound of H. perplexus. It is a remarkable fact that the mounds of a certain species of Eutermes, which are very common amongst those of the Drepanotermes апа Hamitermes, are never molested by Iridomyrmex.

The imagines of the beetle, Cryptodus grossipes, Fairm., have been found in the cells of D. silvestrii, and Mandalotus gerininatus, Lea, has been taken on two Occasions in the nests of H. perplexus. Their relationship to their hosts is not known. Bubaris indemnis, Pascoe, has been found under the walls of termitaria of several kinds, but they appear not to come directly into contact with the termites.

Ciliates (? Trichonympha), which occur in vast numbers in all the workers and soldiers and in many imagines of Mastotermes darwiniensis, Frogg., in Townsville; have not been found in Drepanotermes silvestrii, or im any other locat species of termite.

372 GERALD F. HILL.

Drepanotermes septentrionalis, sp. n. Termes rubriceps, Hill (nec Frogg.), Proc. Linn, Soc. N.S.W., xl, pt. 1, 1915.

Imago.—Head bay, clypeus argus brown; labrum, palpi, antennae and legs buckthorn brown, anteclypeus lighter; thorax and abdominal tergites auburn ; lower surface of abdomen uniform ochraceous tawny ; wings Brussels brown, faintly tinged with yellow behind second vein. а

Head wide, rounded behind and on the sides, flat on the summit, moderately hairy. Labrum moderately large, swollen on the sides, rounded in front. Ante- clypeus yellow, membranous, slightly pointed in front. Postclypeus convex, twice as wide as long, with median suture very distinct. Eyes small, circular (0-376 dia- meter) prominent. Ocelli broadly oval, widely separated from eyes. The small deep impression between ocelli and clypeus pale-coloured. Fontanelle broadly oval, about the size and shape of ocelli, with short indistinct forward extension, similar to that of D. silvestrii, sp. n., but slightly larger. Antennae 18-jointed ; 1st segment moderately long and wide ; 2nd half as long as Ist ; 3rd, 4th and 5th small and closely fused; 3rd and 4th equal to each other, and a little longer than 5th; 6th longer and wider than 5th. 1

Thorax similar to that of D. silvestrii, but more rounded on the sides, similarly clothed. Legs as in D. silvestrii.

Fig. 6. Drvepanotermes septentrionalis, sp. n., wings of imago.

Wings (fig. 6) with the margin ciliate; membrane with many hairs, subcosta very short, hardly extending beyond suture, costa and radius well separated, the latter very dark and connected with the former near the apex of the wing by a few indistinct nervures ; median of the fore-wing branching from the radius within the wing-stump, that of the hind-wing just beyond suture, nearer to cubitus than to radius ; branches of the median and cubitus very irregular and not alike in either fore- or hind-wing.

Abdomen elongate, nearly cylindrical, moderately densely clothed with short reddish hairs; ten dorsal and six ventral plates distinctly visible. Cerci as in D. silvestrii.

Measurements: Length with wings, 15; length without wings, 8; head, with mandibles, 2-06 long ; head, at and including eyes, 1:78 wide; prothorax, 1-03 long, 1-22 wide; fore-wings, 13 long, 3:25 wide; hind-wings, 12-5 long, 3-5 wide; abdomen, 1-73-1-92 wide.

Soldier.—Very like D. silvestrii, sp. n., from which it differs in having the labrum larger and more rounded at the apex, clypeus shorter and less strongly lobed, antennae (fig. 7) of the same number of joints, 7.e., 17 or 18, but the size and shape of the basal joints very distinctly different, viz., in D. septentrionalis the 1st joint is shorter and wider, the 2nd shorter and narrower, the 3rd and 4th very short, together equal

ON SOME AUSTRALIAN TERMITES. 373

to the 3rd in D. silvestrit, 5th about half the length of corresponding joint in the latter species. The head very slightly redder than in the allied species. In size it is intermediate between individuals of D. silvestri? from high stony localities (Castle Hill, Townsville, and those from the low-lying country in the vicinity (Townsville Common).

Fig. 7. Dvrepanotermes septentrionalis, sp. n., basal joints of antenna of soldier.

Worker.—Very like that of D. silvestrii; head more reddish, median suture very obscure, not widening in front to surround the fontanelle ; fontanelle hardly visible ; antennae with 18 joints, stouter, but otherwise similar.

This caste, like the soldier, is intermediate in size between D. silvestri? from the hill-sides and from the plains, as shown by a series of measurements of antennae, mandibles and tibiae.

Biology. he imago was originally described under the name of Termes rubriceps, Frogg., from a de-alated female taken on 11th January 1914 (Hill, 1915), and is here re- described from a perfect specimen of the same sex taken under similar circumstances and in the same locality on 3rd February 1918.

From a very thorough knowledge of all the country on either side of the Darwin- Katherine Railway within 60 miles of the coast, I am convinced that these termites do not construct termitaria, but live in rambling underground galleries as previously described (Hill, 1915).

Drepanotermes daliensis, sp. n. Soldier.—Head very dark, nearly black ; front of head, clypeus, anterior part of

prothorax and mandibles a little lighter, clypeus yellow; antennae, palpi and legs ochraceous tawny.

b

a

Fig. 8. Head of soldier of (a) Drepanotermes daliensis, sp. n.; (b) D. perniger, Frogg. Head (fig. 8,4) very large, widest behind, sloping in slightly to the base of the jaws ; frons flattened, a little rugose, median suture indistinct. Mandibles very long and slender, faleiform, each with a large angular tooth nearer to the base than to the apex

374 GERALD F. HILL.,

and generally directe. l stightiv forward. Labrum large, convex, rounded on the sides to the bluntly rounded apex. Clypeus large, slightiy convex, emarginate in front, divided medially by a 4 зер depression. Fontanelle very indistinct. Antennae (ñg. 9,0) very long and slender, 19- or 20-jointed, rarely 18; Ist joint twice as long And about hali as wile as 211; 2ad nearly cylindrical, one-third longer than 3rd: 3rd narrowest at bass, mU than 4th at apex; 4th shortest of all; 5th a little longer and wider than 4th; 6th neany as long a3 2nd; 7th longer and narrower than 6th.

do E

Fig. 9. Proximal segments of antenna of soldier of a) Drepanotermes perniger, Frogg.; (b) D. daliensis, i 4 S sp. п

Prothorax similar to that of D. silvestrii, but anterior half narrower. Legs long and slender, with scattered hairs except on inner side of tibiae, which are fringed with longer and stouter hairs ; mid-tibiae with two short stout apical setae on upper side, which are absent in hind tibiae; first three tarsals very short, 4th very long ; tibialis purses eee

Abdomen as in D. silvestrii, sp. n.

Measurements :— D. daliensts, sp. n. D. perniger, Frogg.

Head and mandibles, long X 3290-3: 807 8% :196 Thorax and abdomen, long 3-290 25 392610) Mandibles, long 3t ls vt 1-598 Шела авер. - bs 1-175 a 1-034 „мае. із E. 1:645 A 1:598 Antennae te - 4 3:666 25 3-666 Prothorax, long: 2. X 0-658 "n 0-564 а wide s a (5126 сұ 1-081 Tibia (i) "m ra " 1-410 1-457 о 00) ns = T. 1:457 n 1-363 5 it Ae Je X ous de 2.303

Abdomen tes D E 1:05 As --

Workcr.— Colour of head zs in soldier ; clypeus and jaws (excepting teeth) tawny olive; labrum, palpi, antennae, thorax and legs clav-colour.

Head large, rounded behind and on the sides, widest near the middle, a pale coloured and verv distinct median suture extending from back of head forwards, spreading out around the fontanelle, which is a sharply defined, small, broadly oval depression ; frons sloping slightly to the base of the clvpeus, very faintly rugose. Labrum large, very convex, covering apex of jaws, narrower than anteclypeus at base, swelling out sharply in the middle to the rounded apex. Anteclypeus large, middle of anterior margin produced into a point. Postclvpeus large, twice as wide as long, convex, truncate in front, strongly arcuate behind, median suture hardly visible, with verv few hairs. Antennae 19- ог 20-jointed; 3rd, 4th and Sth joints short; 4th shortest.

Prothorax as in soldier, entire surface with stout reddish hairs. Legs long and slender, asin D. silvestrit, sp. n.

ON SOME AUSTRALIAN TERMITES. 375

Abdomen narrow, tapered to the pointed apex, with pale reddish hairs of various lengths. Cerci long and slender.

Measurements :— D. daliensts, sp. n. D. perniger, Frogg. Total length " Head, long 7 - 2.115-2-250 - 1:927 Thorax Ed du long 3-995 бе 3-525 Head, wide сл На 1:739 б 1:692 Antennae .. - T 3:700 m 3:800 Mandibles : left 28 = us 987 long by s :890 long by -658 wide “640 wide right 58 à pa :S93 long by a -799 long by 759 wide :730 wide Prothorax, long .. ес 0:705 ae 0-611 Т wide .. HS 1-034 is 19195 Шора Ка) 2 je e 1:316 hs 1:363 "END o a T 1:222 a 1:316 OH. cus su : 1-924 R 2-068

This species is very closelv S to D. periiger, Frogg. The soldiers are dis- tinguished as follows: In D. daliensis the head is verv much darker; the frons is slightly protuberant and rugose, the middle falling gently into the frontal opening. In D. perniger (Пе. 8,0) the frons is only slightly protuberant, but more rugose. The clvpeus іп D. daliensis is less lobed in front and the furrow dividing it medially is narrower and shallower; the labrum is much shorter and rounder: the antenna has always one, but generally two or three, additional joints, the fourth and fifth of which are very much shorter than in D. perniger (fig. 9,4). The worker may be distinguished from that of D. perniger by its darker head and 19- or 20-jointed antennae.

Type series in South Australian Museum, co-tvpes in author's collection.

NORTHERN TERRITORY: Upper Daly River (H. Wesselman).

Drepanotermes perniger, Frogg.

In his discussion of this species Dr. Mjóberg (1920, p. 69) remarks that the soldiers from different localities show considerable differences in the colour, size and shape of the head, but that he has found no constant characters which justifv him in regarding the pale-headed forms from North Queensland and Kimberlev as specifically distinct from the typical dark-headed forms. Then follows a description of the imago, but unfortunately no locality is given, nor is it stated if his specimens were associated with pale- or with dark- headed soldiers. On page 57 the same author gives a kev for the differentiation of the soldiers of the two hitherto described species of Drepanoter mes, viz., D. perniger, Frogg., and D. rubriceps, Frogg., the former being distinguished by the very long jaws and very broad, projecting tooth, and the latter bv shorter jaws and triangular tooth. The jaws of D. perniger are figured on page 76.

In this paper I have referred to the similarity which exists in the heads of soldiers of certain species the imagines of which show marked specific differences ; for this reason Í cannot agree with the suggestion that pale- and dark-headed forms are referable to a single species. If the imagines described bv Dr. Mjóberg as D. perniger were associated with pale-headed soldiers it is most probable that they are referable to another species. With regard to