106 



MOSQUITOES 



liio-li power in the cast skin. The writer does not care to 

 risk an exi)rossion of opinion as to their function, although 

 possibly it is known, and iliey possibl}^ occur in other dip- 

 terous hirvjp. In the early stages of the larva} they re- 

 semble minute branchial tufts, but no tracheal connection 

 has been found. 



The Pupa. — The accorapanying- figure (Fig. 24) well rep- 

 resents the differences between the pupa of Culex and 



Fig. 24.— Pupa of Anopheles at riijlit ; Culex at left ; enlarged. 

 (Autiior's illustraliori.) 



that of Anopheles. In this stage the insects of tlu^ two 

 genera are not so markedly differiMit as in the larval stage. 

 Structural differences need not W (h^scrilxMl, as they are 

 sufficiently shown in the illustration. The eye will at 

 once be caught by the difference in ]iosition, the pui):i of 

 Culex resting in a more perjieiidicnlar attitude than that 

 of Anopheles ; and the marked difference in shape between 

 the respiratory siphons, which issue from the thorax iu- 



