OF WASHINGTON, VOLUME XIII, 1911. 163 



taxonomic rank of a tribe. I arn inclined to consider it a 

 group-unit of the subfamily Phaniinae. In addition to Comp- 

 silura and Dexodes, Pantel gives here I 'ibrissina demissa. I 

 can add Eucdato? ia and American species of I 'ibrissina or 

 closely allied forms, besides Phorocera doryphorce Riley, 

 whose generic reference is yet in doubt. 



We are indebted to Pantel for first correctly defining and 

 figuring the peculiar structure of the larvipositor and piercer 

 in Compsilura concinnata. I have verified his results in a 

 dissection of Eucelatoria australis. The piercer and larviposi- 

 tor are separate structures, the latter fitting so closely into 

 the base of the former dorsally and being so little chitinized 

 veutrally as to obscure its form. There are heavy, thick 

 muscles at the base of the piercer which move it, these being 

 attached to the last ventral plates. The walls of the end of 

 vagina possess muscles also for injecting the maggot. The 

 larvipositor is a tapering tube, the main chitinized part form- 

 ing the roof, the rest being membranous, with only a narrow 

 longitudinal chitiuous piece or rod forming the floor support 

 and keeping the tube stretched properly below. The larvi- 

 positor is everywhere thickly studded inside with short, sharp 

 spines or spine-like tubercles, which show conspicuously 

 through the membranous portions and are for insuring the 

 exit of the maggot, as they all point posteriorly. The pro- 

 pulsive force is furnished by the vaginal muscles. 



The tip of the larvipositor certainly enters the puncture in 

 the skin of the host made by the piercer. The piercer is 

 grooved on its upper surface, tue larvipositor lying in this 

 groove. The upper or main chitinous portion of the larvi- 

 positor is rather sharply pointed at tip to insure entrance 

 within the puncture, the tip of the ventral supporting rod of 

 the membranous part less so, these two pieces doubtless not 

 opening or separating at their tips until both are well within 

 the puncture, their separation in that position opening the 

 tube for the proper egress of the maggot therefrom within the 

 skin of the host. 



I find no mention by Pantel of the peculiar spinigerous 

 ventral carina of the female, characteristic of all these forms, 

 which appears to be primarily adapted for preventing the 

 skin of the host from slipping forward during the forward 

 thrust of the piercer, this action at the same time facilitating 

 the opening of the puncture as widely as possible. The 

 spines of the carina are directed posteriorly. The posterior 

 part of the carina also receives and protects the sharp point of 

 the piercer, the latter being so perfectly introduced within it 



