﻿SOLOMON ISLANDS TRIPTEROIDES — BELKIN 261 



outside of the Solomons. T. albosc-uteUata Lee and purpurata (Ed- 

 wards) are distinct in the possession of lateral sclerotized comb-plates 

 on the eighth abdominal segment. The larvae of the remaining four 

 species are extremely similar to lipovskyi. Those of brevipalpis Brug 

 can be separated by the bifid dorsal head hairs. T. quasiornata is dis- 

 tinguished by i\\Q: 5- or 6-branched dorsal tufts on the siphon. Having 

 no material for comparison with nissanensis and himaculipes (Theo- 

 bald), I can find no reliable distinguishing characters for these two 

 species, although they seem to differ in minor details according to pub- 

 lished figures and descriptions (Lee, 1946). 



To summarize, the adults of Upovsky resemble most closely those of 

 quasiornata^ while the larvae are very similar to those of bimaculipes 

 and nissanensis. T. himaculipes adults are easily distinguished from 

 lipovskyi by their dark thoracic integument. 



In the Solomons, adults of lipovskyi are readily separated from the 

 other two members of the nitidoventer-grou-p now know by the absence 

 of broad dark scales in front of the wing roots. The larvae of lipovskyi 

 and hinotata are extremely similar, and I can find no reliable characters 

 to separate them. T. distigma (Edwards) is unknown in the larval 

 stage. 



In all probability many additional forms in this group await dis- 

 covery in the Australasian region. Until more are described, it is im- 

 possible to state definitely the interrelationships of the forms known at 

 the present time. 



Variation. — The type series from Guadalcanal exhibits striking lack 

 of variation in the majority of the characters studied, although adults 

 are available from several different habitats and were collected at 

 different times of the year. The thoracic integument is almost in- 

 variably light orange, but occasionally dark-orange specimens are 

 found. The posterior pronotum shows from one to several broad 

 scales in more than half of the specimens examined. The abdominal 

 silvery markings are also quite constant. The ninth tergite of the male 

 shows a great deal of variation in shape and in the size and number 

 of bristles on the lobes. It appears that the majority of species of 

 the nitidoventer-group have very similar structure of this sclerite. 

 Therefore it would seem advisable not to rely on minor differences in 

 the ninth tergite until large series of all species are studied. In the 

 larvae, the usual variation in the numbers of spikes in the stellate 

 tufts is noted and the hairs of the terminal abdominal segments show 

 some variation. No correlation could be found between any of the 

 variations noted and the habitat. 



No geographical variation of note is exhibited by this species ex- 

 cept for a somewhat darker thoracic integument in about half the 

 New Georgia specimens. Tliis may be due to a certain extent to the 



