106 



3I0SQUIT0ES 



high power in the cast skin. The writer does not care to 

 risk an expression of opinion as to their function, although 

 possibly it is known, and they possibly occur in other dip- 

 terous larv8e. In the early stages of the larvae they re- 

 semble minute branchial tufts, but no tracheal connection 

 has been found. 



The Pui^a. — The accompanying figure (Fig. 24) well rep- 

 resents the differences between the pupa' of Culex and 



Fig. 24.— Pupa of Anopheles at right ; Cnlex at left ; enlarged. 

 (Author's illustration.) 



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

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

 Structural differences need not be described, as they are 

 sufficiently shown in the illustration. The eye will at 

 once be caught by the difference in position, the pupa of 

 Culex resting in a more perpendicular attitude than that 

 of Anopheles ; and the marked difference in shape between 

 the respiratory siphons, which issue from the thorax in- 



