INSECTA. 251 
The “ piercing and sucking” mouth parts are well shown 
in the gad-fly (Zadanus). The upper lip (4adrum) mandibles 
and maxille are lengthened and produced into sharp stylets, 
whilst the labium is produced into a long hairy proboscis 
with two terminal lobes. In gnats the “piercing” stylets 
are best developed, whilst in flies, such as the house-fly, the 
‘sucking ” proboscis is large and the stylets are small. 
Fig. 171.—WHEAYT MIDGE (Cectdomya tritict). 
A, Larva in wheat-flower; B, larva in grain; C, larva; D, fly. 
