ox SOME AUSTRALIAN TERMITES. 375 



Abdomen narrow, tapered to the pointed apex, with pale reddish hairs of various 

 lengths. Cerci long and slender. 



Measurements : — 



This species is very closely related to D. perniger, Frogg. The soldiers are dis- 

 tinguished as follows : In D. daliensis the head is very much darker ; the frons is 

 slightly protuberant and rugose, the middle falling gently into the frontal opening. 

 In D. perniger (fig. 8,6) the frons is only slightly protuberant, but more rugose. The 

 clypeus in D. daliensis is less lobed in front and the furrow dividing it medialh* 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, a). The worker may be 

 distinguished from that of D. perniger by its darker head and 19- or 20-jointed 

 antennae. 



Tvpe series in South Australian Museum, co-types in author's collection. 



Northern* Territory : Upper Daly River {H. Wesselman). 



Drepanotermes perniger, Frogg. 



In his discussion of this species Dr. MjQberg (1920, p. 69) remarks that the soldiers 

 from different localities show considerable difterences in the colour, size and shape of 

 the head, but that he has found no constant characters which justify him in regarding 

 the pale-headed forms from North Queensland and Kimberley as specificalh* 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 key for 

 the differentiation of the soldiers of the two hitherto described species of Drepanotermes, 

 viz., D. perniger, Frogg., and D. rubriceps, Frogg., the former being distinguished 

 b\- the very long jaws and very broad, projecting tooth, and the latter by 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 difterences ; for this 

 reason I cannot agree with the suggestion that pale- and dark-headed forms are 

 referable to a single species. If the imagines described by Dr. Mjoberg as D. perniger 

 were associated with pale-headed soldiers it is most probable that they are referable 

 to another species. With regard to characters given for the soldiers of D. perniger 

 and D. rubriceps, it may be said that the shape of the mandibular tooth is 

 variable in specimens from the same colony, and that the form figured by 

 Dr. Mjoberg for D. perniger is one commonly found in D. rubriceps, D. silvestrii, 

 D. scptentrionalis and occasionally in D. daliensis. 



