WHAT WE SHOULD KNOW ABOUT MOSQUITO BIOLOGY 271 



'The larvas live in ground-pools, usually in tidal marshes. Breeding 

 alsa occurs inland. Below New Orleans it is an abundant pest in the 

 salt and brackish water marshes, where it occurs in undiminished numbers 

 even in the winter. 



Anopheles pseudopunctipennis larva differs but little from the pre- 

 ceding but may be separated in the table which follows. 



This species is somewhat discriminating in choice of breeding place. 

 It prefers as a rule water of great purity and rapidity of current. The 

 larval food is by preference the soft green algae. It has been found, 

 however, in irrigating ditches, in clear quiet pools formed by the over- 

 flow of a watering trough, in ditches, pools and puddles, in tanks, well- 

 holes and spring-holes full of algae. 



Anopheles pwnctipermis larvae (fig. 51) are found in all sorts of water 

 in ground-pools and streams and occasionally in artificial receptacles. 

 The larvae are found all the season, breeding being continuous until winter. 



Fig. 51. — Larva of the malaria mosquito, Anopheles punetipennis. (After Howard, 



Dyar and Knab.) 



The larvffi occur most commonly in swamps containing algae. Larvae 

 have been found repeatedly in rain puddles, the water muddy and without 

 trace of algal growths. 



Anopheles quadrimaculatus larva is most like that of ptmctipenms. 

 The larvje occur in natural collections of water of a more or less per- 

 manent nature. They often occur in the same locations as punctipenmis 

 but are more addicted to permanent stagnant water, such as the edges 

 of sluggish rivers and marshes containing algae, less to springs and 

 running water, and do not occur in temporary ground-pools filled by rains. 



The larvse of Anopheles are to be distinguished from Culex and Aedes 

 by the habit of feeding. The two latter genera have larvas with long 

 breathing tubes by which they hang from the surface of the water with 

 the head downward, and feed on the life under the surface. Anopheles 

 larvae have very short breathing tubes. They are surface feeders and 

 are held to the surface by the tube and the fan-shaped abdominal tufts. 

 The head is turned completely over with the mouth uppermost in the act 

 of feeding. 



