INSECTS 



403 



Gnats (Culicidce). The life-history of one species (Culex annu- 

 latus] is represented in fig. 924. The female, when about to 

 lay her eggs, holds firmly to some object by means of the first 

 two pairs of legs, the last ones being stretched out at the back 

 and crossed over one another (see figure). In the angle between 

 their upper ends the elongated eggs are successively deposited, 

 sticking together after leaving the body. As their number in- 

 creases, the legs are gradually uncrossed and at last lie parallel 

 to one another. The mass of eggs now floats away from be- 

 tween them in the form of a canoe-shaped 

 raft. The wriggling larva makes its way 

 E. 



Fig. 924. Life-history of Ringed Gnat (Culex annulatus) 



A. Raft of eggs, X 5; B. separate eggs, X 24; B. a, cup-shaped float attached to lower end of egg, X 160; 

 C. D. and E. (all X 3), larva, pupa, and female laying eggs. 



out from the under side of the egg, which is provided with a 

 kind of lid, and later on becomes a floating pupa. The way in 

 which these stages breathe has already been described (see vol. ii, 

 p. 442). The pupa is able to move when alarmed, on which 

 point Hurst (in The Pitpal Stage of Culex) makes the following 

 remarks: " The pupa is sensitive to light, and immediately darts 

 backward when a shadow falls upon it suddenly. The move- 

 ments, however, though very rapid, are devoid of anything like 

 steering. The larva had to steer in its search for food, but the 

 pupa has simply to get out of the way of danger, and the direc- 

 tion of its flight is of little importance, though, since the move- 

 ment is always backward with reference to the pupa, it is chiefly 

 downward with reference to the outer world. A sudden very loud 



