OTHER GENERA OF 3WSQUIT0ES 151 



parisou with larva of Culex, Avliicli it resembles more 

 nearly than that of Anopheles, it will be seen that the 

 breathing tube is longer ; that the anal flaps are longer 

 and more pointed, and the hair fringe on the under side 

 of the last segment of the body is much longer and 

 denser, while the mouth-i^arts are quite different. Tlie 

 jaAvs are sharply toothed, and very long, and are used in 

 the mastication of food. Other mosquito larvfe feed upon 

 spores of alga3 and other small particles which appear to 

 require no mastication, but this larva descends to the 

 bottom of the water and has been noticed to grasp a bit 

 of water-plant half an inch long and actually to chew it. <■ 



The duration of the pupal stage was from four to live 

 days, and the adult insects issued on September 27tli and 

 28th. Young larvae were also found in this sending, and 

 one of them is shown in Figure 40. 



The breeding-places in which these larvae were found 

 were small depressions in the bed of a small stream, and 

 similar hollows in certain small ponds, all of which were 

 dry the greater part of the summer. After they first 

 dried in the spring they were barren of fish and vegeta- 

 tion. Mr. Seal is satisfied that the insect is rare in the 

 vicinity of Philadelphia, and thinks that possibly he may 

 have brought this species from the South, as he is in the 

 habit of shipping large quantities of aquatic plants from 

 the South, from January 4th to about May 10th of each 

 year. He has a place some miles from Delair where he 

 grows Cabomba. The plant is very dense, and the creek 

 is full of fish, but in the water on top of the plant, which 

 grows to the surface, are large numbers of mosquito 



