INSECTA 



107 



which after about a week are in turn transformed into awk- 

 ward pupae. Though the larva and pupa live in water, 

 they breathe air and must therefore come to the surface 

 from time to time. The adult mosquito lives a longer or 

 shorter time, depending on the amount of food it is able to 

 secure and how soon it finds a mate. "Some species are able, 

 under favorable conditions, to pass through their entire life 

 cycle in a week (egg, one day; larva, four; pupa, two; adult, 



FIG. 52. Diptera, Nematocera. Crane fly and larva; mosquito with 

 larva, and pupa; willow-cone gall fly; midges with larva and pupa. 



variable). Mosquitoes are very prolific breeders; it is 

 possible for one pair to produce two hundred million in 

 four months. An adult mosquito may live for five months, 

 perhaps longer. It is thus able to exist long after breed- 

 ing ponds have dried up, and can hibernate during the 

 winter. Male mosquitoes do not suck blood. They usu- 

 ally subsist on plant juices, and will sip water, wine, etc. 



