﻿SOLOMON ISLANDS TRIPTEROIDES — BELKIN 227 



The prescutellars usually are represented by two pairs of strong bristles 

 but may be increased to four pairs. The white scaling of the posterior 

 pronotum is usually restricted to the lower third of this sclerite, but 

 in large, vigorous specimens it may extend to almost half the sclerite. 

 One female examined had well-developed scales on the anterior margin 

 of the clypeus. In the larvae, the most obvious variation is noted in 

 the development of the maxillary spines and the stellate tufts, par- 

 ticularly on the abdomen. Some specimens show stellate hairs that 

 are almost twice the length of those in others. The pigmentation of 

 the stellate tufts varies considerably, as well as the number of branches. 

 Tlie number of comb scales is not constant even on the two sides of an 

 individual. They vary anywhere from 6 to 11 on each side. All these 

 characters were found to overlap similar characters in stonei. 



On the other hand, the following characters showed no overlapping 

 with other species: In the adults, simple male palpi, shape of the 

 ninth tergite of the male ; in the larvae, development of dorsal hairs 

 on the middle abdominal segments, number of pecten teeth, pigmenta- 

 tion and length of siphon, absence of spike hairs from the metathorax, 

 and the small size of the postmaxillary hair on the head. Whereas 

 in mathesoni all the structures associated with the siphon are strongly 

 developed and the head, thoracic, and abdominal hairs are reduced, 

 in stonei and toroMnae the reverse is true. 



T. mathesoni shows no geographical variation that has not been 

 noted in individuals from Guadalcanal. Specimens examined from 

 eastern and western New Georgia, Roviana, and Bougainville conform 

 very well with the type material. 



Specimens examined : 12 individual rearings, 148 adults, 156 larvae, 

 57 pupae. 



Biology. — T. mathesoni larvae have been collected only in the leaf- 

 axils of wild species of taro {Colocasia and Alocasia sp.) throughout 

 the year. Usually only a few full-grown larvae are present in a leaf- 

 axil. The larvae are predaceous and cannibalistic. They normally 

 rest on their backs at the bottom of their breeding places with the en- 

 larged, spined maxillae projecting forward and upward from the 

 head. In the laboratory they have been observed to catch and slowly 

 consume the larvae of Uranotaenia quadrimaculata Edwards as well 

 as individuals of their own species. When denied other larvae for 

 food, nearly mature individuals will, nevertheless, complete their 

 development, pupate and emerge as adults, although in such cases the 

 aquatic cycle is greatly prolonged. The larval stage, under laboratory 

 conditions and with adequate food, is approximately three weeks. The 

 pupae, which are extremely large compared with the size of the adults, 

 take several days for development. 



In the field the larvae are easily recognized by their large size, elon- 



