WHITE-PINE LEAF-LOUSE. 91 



than the males, continue to hatch in a very gradual manner, some 

 nnhatched eggs being found under the scales all through the 

 mouth of August, and as late as the middle of September, at 

 which time I found a considerable number of scales, with from 

 two to six unhatehed eggs. But before the close of this month, 

 the females from the eggs first hatched have completed their de- 

 velopment, and have begun to deposit their eggs for the next 

 Spring's brood. So that there is an almost continuous brood of 

 these insects throughout these two months. I cannot perceive 

 what is gained in the economy of this insect by this protracted 

 hatching of the Summer brood — since the product of this brood 

 all hybernate in the egg state — unless it be to baffle the opposi- 

 tion of mankind. For if they had this end expressly in view, 

 they could not pursue a more etfeclual course, since it follows that 

 at whatever time we make our applications for the purpose of des- 

 troying them, some of them will elude our assaults. If we make 

 our applications early, the unhatehed eggs will be safe beneath 

 the maternal scale. If we make them later, those first hatched 

 will have found protection under the scales of their own forma- 

 tion. The unsatisfactory results of my own experiments go to 

 confirm this view. 



On the 6th of August, that is at about the close of the hatching 

 of the male-producing eggs, I applied to two branches of a badly 

 infested tree, a wash, composed of common fish brine, diluted at 

 the rate of one pint to two gallons of water, and to two other 

 branches, the same wash, but of double the strength. Again, on 

 the 23d of August, after the greater proportion of female produc- 

 ing e^rgs had hatched, I applied to other branches, soap-suds of 

 the strength of one gill of soft soap to a gallon of water. I also 

 wet a branch with water and dusted it thoroughly with unleached 

 ashes. 



Upon examining the leaves upon these several branches, late in 

 the Fall, I could not perceive much difierence in the result of the 

 different experiments. Upon all of them could be seen, still adhe- 

 rent, the dead and discolored remains of a considerable number of 

 email individuals whose development had been arrested whilst in 

 the incipient larval state, and also a larger number which had at- 

 tained their normal growth, the washes having failed to reach 

 them for the reasons above stated. It did not appear that any of 



