and Life History of Psychoda sexpimctata. 307 



la the Chironomus fly the antennary muscles are 

 attached to the walls of the chitinous invaginations them- 

 selves, an interesting point of difference from Psychoda. 

 A somewhat similar pair of structures has been described 

 in some other insects, notably in Corydalis* 



Each antenna consists of fifteen joints ; of these the 

 first is cylindrical, the second globular, and the others 

 flask-shaped, with the exception of the last three, which 

 are globular. From the globular part of each joint arise 

 a number of curved, radiating setse. 



The fly apparently does not feed at all, since no traces 



Fig. 13 ( x 20). 



Side-view of male fly. The wing is extended and cut short ; the legs cut 

 short. The lower figure shows the genital armature in plan. 



of food have been observed in its reduced alimentary 

 canal, nor has it ever been seen to take in food. The 

 mouth-parts (Fig. 12) are somewhat similar in arrange- 

 ment to those of Culex, but are very largely atrophied. As 

 in most Diptera, there is a roughly conical rostrum, which 

 bears an elongated, triangular labrum, behind which is 

 the short, bilobed labium. This is fringed with numerous, 

 * Waterhou.se (1895). 



