Insects and Human Health 



537 



one hundred to four hundred eggs. It floats on the surface of 

 the water like cork. The eggs of the Stegomyia are only slightly 

 less massed. The Anopheles oviposits her eggs singly (Fig. 162) . 

 Each egg, the shape of which is regular and elliptical at both 



FIG. 162. Life story of the Anopheles mosquito, the carrier of the malaria 

 plasmodium. Characteristic positions of the adult mosquito, the pupa and the 

 larva. Compare with the Culex mosquito, Fig. 161. 



ends, lies on its side and floats on the surface of the water. They 

 usually remain close together. The Anopheles lays from fifty 

 to a hundred eggs at a time. 



Exercise : Life history of the mosquito. Collect mosquito eggs. 

 Get some larvae or wigglers from a pond, and a quart of the water in 

 which the larvae are found. Mosquito eggs may be secured by setting 

 a pail of not too clean water with a few small bits of wood floating on 

 the surface, in places frequented by mosquitoes. Examine in the 

 morning and when you find eggs, transfer them to the breeding jars. 

 If you have a good supply of eggs and larvae, take out at stated inter- 

 vals one or two to preserve and arrange them to show stages of develop- 

 ment. A record of dates, temperatures, and condition of the water 

 should be kept, and the important data summarized on the labels 

 pasted on the jars. 



