7 8 



Insects and Disease 



THE LARVAE 



When the larvae are ready to issue they burst 

 open the lower end of the eggs and the young wrig- 

 glers escape into the water. The larvae are fitted 

 for aquatic life only, so mosquitoes cannot breed 

 in moist or damp places unless there is at least 

 a small amount of standing water there. A very 

 little will do, but there must be enough to cover 

 the larvae or they perish. 



The head of the larvae of most species is wide 

 and flattened. The eyes are situated at the sides, 

 and just in front of them is a pair of short antennae 

 which vary with the different species. 



The mouth-parts too vary greatly according to 

 the feeding habits. Some mosquito larvae are 

 predaceous, feeding on the young of other species 

 or on other insects. These of course have their 

 mouth-parts fitted for seizing and holding their 

 prey. Most of the wrigglers, however, feed on 

 algae, diatoms, Protozoa and other minute plant 

 or animal forms which are swept into the mouth 

 by curious little brush-like organs whose move- 

 ments keep a stream of water flowing toward the 

 mouth. 



Another group containing the Anopheles are 

 intermediate between these two and have mouth- 

 parts fitted for feeding on minute organisms as 



