The Eggs of " Culex " and " Anopheles " 



of the insect's hind legs, so as to form an elongated boat-shaped 

 mass consisting of several hundred eggs joined to one another by 

 their edges. When this egg-boat or egg-raft has been constructed 

 the insect allows it to drop into the water, where it floats as a 

 small oblong boat-shaped body somewhat raised at each extremity 

 (PI. I., Figs. 4, 5, 6). The shape and character of these egg-rafts 

 vary in different genera. In the genus Culex (sub-family Culicina) 

 they are broad and more or less oval in shape ; in the genus Tcenior- 

 hynchus (sub-family Culicina} they are said to be very elongated 

 and to resemble a racing skiff in shape (Stephens and Christo- 

 phers) ; in the genus Coreihra (sub-family Corethrina), the eggs are 

 collected together in flat, round, jelly-like masses. 



The eggs of all " anopheles " mosquitoes, on the other hand, 

 as well as those of a few " oule* " moquitoes (viz., those of the 

 genera Stegomyict, Panoplites, Psorophora and Janthinsoma of the 

 sub-family Culicina) are not collected together into a mass of defi- 

 nite shape before deposition. The reason of this is that the indivi- 

 dual eggs do not stick together, so that when laid on a solid object 

 they form only a piled up mass, and when 

 laid on water they quickly separate from one 

 another and float as isolated elements (PI. I, 

 Fig 1 ). Owing to physical causes, the eggs, 

 when deposited on water, may arrange 

 themselves in fairly definite star-shaped pat- 

 terns or in rows, but more frequently they 

 are scattered irregularly over the surface 

 of the water. The individual eggs which 

 compose an egg-raft of " culex " mosquitoes, 

 are oblong in shape, and broader and more 



, -.->, Fig. 1 {after Daniels). 



rounded at one end than at the other ( PI. 



I, Fig 7). When joined together to form the raft they lie verti- 

 cally with the narrow end out of the water and the broad end from 

 which the larva escapes submerged. The eggs of mosquitoes of 

 the genus Panoplites (Fig. la) have one end terminating in a fine 

 point ( Daniels), and those of the genera Stegomyia and Psorophora 

 (Fig. 1, I & c) are peculiar in that, besides being more or less oval 

 in shape, they possess a rim of cells, somewhat resembling the rim 

 or frill present in " anopheles " eggs. 



[7 



