EGGS OF MOSQUITOES 195 



depositing the eggs collect them together into a regularly arranged heap 



the so-called egg raft. The female in doing so crosses 



her hind legs arranging each egg as it is passed out. Early 8ta e8> The 



P00Q iPlatpi; XXXIV 



The egg mass of Culex fatigaus (Plate XXXIV, fig. 9) and xm) 

 is a typical example of this kind of egg raft ; it is 

 boat-shaped and consists of from 200 to 400 eggs. 



The egg (Plate XXXIV, fig. 5) is an elongated ovoid, broadly rounded 

 off at the end which lies on the surface film of the water, and which has 

 attached to it a delicate globular process, the micropilar apparatus. 

 The larva escapes from the broad end, and is thus able to dive 

 straight into the water. When first laid the eggs are white, but they 

 soon become dark grey. The individual eggs can be readily separated, 

 and the whole mass breaks up when the larvae hatch out. 



Many culicines lay their eggs singly, depositing them irregularly 

 on the surface of the water, or at its margin. The eggs of these species 

 show great structural variation. Some are long and pointed, as those 

 of Mansonia and Panoplites ; in Megarhinus they are club-shaped, while 

 in others they are either spindle-shaped or oval. The eggs of Stegomyia 

 (Plate XXXIV, fig. 7) are surrounded by a frill containing air, and in 

 Janthinosoma they are covered with minute spines. 



The eggs of Anopheles (Plate XXXIV, figs. 2, 8 and 10), which are 

 also laid separately, are characteristic, being as a general rule boat- 

 shaped ; the upper surface is flattened in the transverse diameter, and 

 is surrounded by a delicate striated rim or frill. One end of the egg 

 is usually broader than the other. Attached to the sides of the egg 

 are the floats, which are small ribbed structures containing air ; they 

 are present on the majority of anopheline eggs, though there are some 

 remarkable exceptions. Stephens and Christophers have drawn atten- 

 tion to the variation in the shape and position of the floats, and in 

 the width and extent of the frill on the upper surface. They have 

 thus been able to distinguish the eggs of most of the Indian anophe- 

 lines. 



When examining the egg of an Anopheles it is important to note 

 the character of the frill, whether it is broad or narrow, and whether 

 the floats encroach on it. The size and position of the floats should 

 also be noted, as well as any other special markings on the surface of 

 the egg. 



The body of the culicid larva shows a greater resemblance to the 

 adult than is usually the case in the Diptera, being divided into head, 

 thorax and abdomen. In their general structure the larvae of the 



