308 



Mr. J. A. Dell on the Structure 



short, finger-like processes, and its edges are rolled for- 

 wards so as to enclose a pair of maxillse. The maxillae 

 are short, styliform, and fringed with setce ; near the base 

 they give rise to a pair of long, four-jointed maxillary 

 palps. The styliform maxilla probably corresponds to the 

 lacinia of typical forms ; there does not appear to be any- 

 thing to correspond to cardo and stipes. On the front of 

 the labium is a minute, triangular hypopharynx or lingua. 



The Thorax of the Fly. 

 As usual in Diptera, the thorax of Psychoda (Figs. 



Fig. 14. 



Longitudinal section of thorax of Psychoda (upper fig.) ; ditto of 

 Cliironomus (lower fig.). 



13, 14) consists of a small pro thorax, an enormous meso- 

 thorax, and a small metathorax. The prothorax is little 

 more than a ventral hoop, containing the muscles of the 

 first pair of legs. Ventrally and laterally its hinder 

 margin is indicated by a suture. Dorsally its boundary 

 is uncertain ; it certainly, however, lies in front of the 

 first spiracle, 



