﻿234 PROCEEDINGS OF THE NATIONAL MUSEUM vol. lOO 



(965-1) in coconut shells, mouth of Balasuma River, April 30, 1945 

 (M. Cohen, F. B. Wysocki, J. J. Cuccio, V. E. Roa). Paratypes to be 

 deposited in the collections of Cornell University, British Museum 

 (Natural History) ; U. S. National Museum ; and Council for Scientific 

 and Industrial Research, Canberra, A. C. T., Australia. 



This species is named in honor of Dr. Alan Stone, who gave encour- 

 agement and assistance throughout this study. 



Taxonomic discussion. — T. stonei is a member of the /?Z^pe5-group of 

 Rachisoura and resembles closely the other two members of the group 

 found in the Solomons. 



The structure of the male palpi (four to six long bristles on the 

 apical segment) will serve to distinguish stonei from all other species 

 of this group. T. torokinae resembles it in this respect, but the bristles 

 on the apical segment of this species are much more numerous, usually 

 at least 25 or more. The ninth tergite of the male is very distinct from 

 that of mathesoni., but it can be separated from torohinae only by the 

 flattened bristles in the latter. The females of stonei cannot always be 

 separated from those of mathesoni as the amount of light scaling on 

 the posterior pronotum shows considerable variation. The female 

 palpus of stonei som^etimes shows two slender bristles at the apex of 

 the terminal segment. In mathesoni the bristles are always absent, and 

 in torokinae they are three or four in number and arise separately, 

 while in stonei they arise side by side. The larvae of stonei are easily 

 separated from mathesoni by the characters used in the key, but they 

 are apparently very similar to those of torohinae. 



Other features distinguishing stonei from Papuan forms are dis- 

 cussed under mathesoni. 



Variation. — As with mathesoni^ a study of 28 individual rearings 

 from Guadalcanal reveals considerable variation in individuals of 

 this species. In the adults the postnotal bristles are frequently absent, 

 the spiraculars may be increased to six, the upper sternopleurals are 

 often absent, when present they are very weak. The prescutellars 

 may be increased to four pairs in the more vigorous individuals. Large 

 specimens show completely white posterior pronota, but in smaller, 

 weaker specimens the light scaling may cover slightly less that the 

 lower half of this sclerite. The maxillary spines of the larva vary a 

 great deal in size; frequently the small spines are considerably en- 

 larged, so that there is little difference between adjacent spines and 

 little differentiation of the largest spine from the others. The abdomi- 

 nal and thoracic stellate tufts are quite variable in length, as well as in 

 the number of branches, but are always black. The number of comb 

 scales is not constant, even on the two sides of the same individual, but 

 the variation in number is not so great as in mathesoni. 



T. stonei shows considerable geographical variation, at least in the 

 female. All the specimens of this sex collected on Arundel Island have 



