﻿The main results of the above investigations 



on the life- history of some muscoidean 



flies parasitic on insects. 



The preceding paper contains descriptions of the meta- 

 morphosis in some species of the groups Tachinince and 

 Dexiinæ, together with information on the biology of 

 the larvæ. 



1, The larvæ. 



All the larvae examined pass during development through 

 three stages for which there can be established general 

 characters, based on the pharyngeal skeleton and the 

 spiracles. 



First stage. The pharyngeal skeleton terminates in 

 front in a single, pointed, median tooth: on each side of 

 this there is a little hook which is not connected with the 

 pharyngeal skeleton by an articulation. (Figs. 11,35). Poste- 

 riorly the pharyngeal skeleton is divided into a pair of 

 upper and a pair of lower pharyngeal plates. There is an 

 arched, quadratic plate below the anterior part of the 

 pharyngeal skeleton with which the plate is not in firm 

 connection. Only one pair of spiracles is present, situated 

 on the last segment; each spiracle terminates in tAvo knobs, 

 placed near together (Fig. 12). 



Second stage. The anterior median tooth of the 

 pharyngeal skeleton has disappeared, and the skeleton is 



