324 



THE AMERICAN MONTHLY 



[Oct. 



are deposited beneath the scale, which in time hatch, 

 and the young larvjB make their escape and migrate 

 to different parts of the plant. In the San Jose 

 scale the eggs are fairly well formed, a few at a time, in 

 the body of themother (fig. 8). What takes the place of 

 the egg shell consists of a very delicate and thin mem- 

 brane — the amnion, which encloses the developing larvae 

 and which at the time of birth is cast off, and remains at- 



Mytilaspis pomonim : a, adult male ; b, font of same ; c,yonn? larva; d, auteuuaj of same ; e, 

 adult feiiialii takeu from scale ; — a, c,e, greatly eulargeil ; b, d, still more enlarged. 



tached to or partly within the ovidact. The amnion is 

 probably pushed out by the next larva in turn. Each fe- 

 male gives birth to from 9 to 10 larvsB in twenty four 

 hours and as this extends over a period of six weeks it 

 leads to a very confusing intermingling of generations 

 and renders it difficult to make observations, but by iso- 



