D DRAGON-FLIES 



a hand lens to note the arrangement and appearance 

 of the eggs. How many are there in the mass? 



The eggs should be kept under pretty constant obser- 





Fig. I. — The mosquito, Culex sp. ; showing t-ggs (on surface of water), 

 larvse (long and slender, in water), pupa (large-headed, at surface), and 

 adult (in air). (From living specimens.) 



vation, for hatching is likely to take place soon after 

 they are brought into the schoolroom. Ordinarily they 

 hatch in from twelve to twenty-four hours after they are 

 laid. They may, of course, hatch at night. But if the 

 hatching occurs during the day it can be easily observed. 



