540 Introduction to the Study of Science 



content frozen hard, you may secure a supply of hibernating 

 larvse. These, if the ice be very slowly melted and the water 

 gradually warmed, will revive and begin their life routine. 



267. The pupa. The pupal stage lasts from one day to 

 as many as conditions determine. The pupa bobs about near 

 the surface of the water, eating nothing, but still wonderfully 

 active if necessary. A tempting bite for fish and the water 

 boatman, it must be ready to dart like a flash to safety. Try to 

 catch them in water. 



In the pupal state one may discern, delicately outlined within 

 the thin covering, the head, wings, legs, and antennaB of the 

 adult mosquito. The usual position of the pupa near the 

 surface of the water shows a new way of getting air. The old 

 tube is replaced by a pair of ear-like tubes issuing from the back 

 of the body or thorax. In the Anopheles pupa (Fig. 162), these 

 are long and sharp at the ends. In the Culex (Fig. 161), they 

 are conical, like gently tapering funnels. 



268. The adult. The adult mosquito issues after twenty- 

 four hours or more. For half an hour its wings are unfit for 

 use, and it remains floating on the pupa skin at the mercy of 

 wind or wave or any enemy. Slight rippling of the water 

 upsets it and causes it to drown. Food during this stage is 

 obtained from the water or any substances into which it happens 

 to thrust its beak. When its wings are strong, it finds food in 

 the vegetation near its birthplace, the juices of plants and 

 fruits being its main supply. 



The ratio of males to females is probably seven to one. The 

 male remains near the place of birth, feeding and associating 

 with females for a few days, when he dies ; or he may complete 

 his life span, which is very short, without feeding. The female 

 soon makes longer journeys in search of food. She usually 

 derives sustenance from the juices of plants and fruits, but 

 apparently prefers a diet of the blood of animals and men. 

 After a period of two weeks or more, she usually seeks her 

 birthplace, or, if not that, any suitable place where she may 



