II 



FLIES WITH AQUATIC 



183 



in which the whole of the aquatic life of the Simulium 

 is passed. An inactive and exposed pupa, Ir-ke that 

 of Chironomus, may fare well enough on the soft 



FIG. 64. Simuiium. A, larva in outline, with salivary glands. B, coronet of hooks 

 at tail-end of larva. C, part of silken cocoon of pupa, showing its interwoven 

 fibres, the product of the salivary glands. 



muddy bottom of a slow stream, but such a pupa 

 would be swept away in a moment by the currents 

 in which Simulium is most at home. Before pupa- 

 tion the Insect constructs for itself a kind of nest, 



