DIPrEROUS FAMIliY PANTOPHTHAI-MID/^i. 



557 



attention to the accompanying figure (text- fig. 1). which displays 

 the chief features in the external morphology of a larva — probably 

 nearly adult — of another species of the genus Pantophthahnus . 

 This larva, which is preserved in spirit, is 32-5 mm. (just over 

 1| inch) in length, while the average ventro-dorsal diameter of 

 the body-segments is 9'75 mm. It was taken, with at least five 

 other larvc-e of the same kind, in the Island of Trinidad, B.AV.I., 

 in borings in the trunk of an Erythrina, a leguminous tree, which 

 attains a height of from 15 to 20 feet. 



Text-figure 1. 



Larva of FantopUhalmus tabaninus Thnnb. (lateral view), from boring in trunk of 

 Jirj/tJirina tree {lU. comllodendrum L. ?), Trinidad, B.W.I., March 1912 

 {F. IF. Urich). X 2k — From specimen Idndly lent by Dr. Hugh Scott, 

 University Museum of Zoology, Cambridge. 



a, labrum; b, left mandible; c, left anterior (prothoracic) spiracle or stigina; 

 d, dorsum of 8th post-thoracic segment, vphich is very heavily chitnnzed ; e, t lebrig s 

 "finger-shaped bodies"— in all probability an auxiliary respiratory apparatus, 

 employed when the posterior stigmata are unable to function, owmg to the larval 

 tunnel being full of sap. , r « i -n » 



The stout labrum and the extremely powerful mandibles togetlier torm a clriU, 

 l)y means of which the larva is able to bore in solid wood; the equally heavily 

 chitiiiized dorsum of tlie Sth post-thoracic segment closes the tunnel from behind, 

 and protects the larva from an attack in the rear. The posterior stigmata open on 

 tlie posterior (ventral) surface of this segment, in a mouth-like chamber between it 

 and the 9th post-thoracic segment, which bears the " finger-shaped bodies.' When 

 tlie latter segment is in the position shown in the figure, the posterior stigmata are 

 completely closed. ^ e ,.\ 



In the adult Pantophthalmid larva, the number, size, and arrangement of the 

 backvvardly directed spines on the Sth post-thoracic segment^ perhaps afford 

 characters of specific importance (c/. IJrauer, loc. cit. Taf. ii. figs. 25 a, 25 b). 



In the Trinidad larva, the longitudinal strips of chitin em- 

 bedded in the integument of the prothoracic segment, to which 

 the striped appearance of the latter is due, are reddish brown, 

 while the powerfully developed labrum and mandibles, and the 

 heavily chitinized dorsal surface of tlie Sth post-thoracic segment 

 are deep black ; the prevailing tint of the remainder of the body 

 is that of old ivory. Tliere can be little doubt, however, that 

 prolonged immersion in alcohol has had a bleaching effect, snice 

 Fiebrig describes the nine "soft" body-segments in the larva 

 discovei-ed by him as " bluish green," owing to the " intense blue 

 tint " of the abundantly developed fat-body ; it is also worthy of 



