STATE HORTICULTURAL SOCIETY. 189 



eggs and perishes ; that these eggs hatch in the spring as soon as the 

 ground becomes sufficiently warm, and the colony is continued through 

 tlie season by the viviparous propagation usual with the Aphides; that in 

 the autumn following winged individuals again appear, and, leaving the 

 ground, seek new homes. 



So far as the method of propagation is concerned, it has been shown 

 bv Dr. W. M. Smith, of New York, that it differs slightly from the true 

 Aphides, in that the young larvae produced by the agamic females are 

 inclosed in the thin egg-shaped covering heretofore mentioned, from 

 which they have to free themselves in a manner analogous to hatching. 

 The remains of this covering may often be seen attached to the tip of the 

 abdomen, and is doubtless the supposed cottony secretion alluded to by 

 Dr. Fitch in his description of the young larvae. The fact of acquiring 

 wings is in itself an evidence that these individuals, at least, are intended 

 bv nature to come to the open air with the power to roam and seek new 

 localities. It is supposed by some that those on the trunk and branches 

 remove to the roots as winter approaches. I have strong doubts on this 

 point, unless by "removing" is meant that the mature winged females, 

 which appear among these colonies at the approach of winter, after pair- 

 ing, deposit their eggs on the roots. Mr. Verrill states, in The Practical 

 Entomologist, that he found healthy and active lice of all sizes, and busily 

 engaged in sucking sap, on the under side of the branches as late as De- 

 cember II, after two snow storms and many cold rains and freezing niglns. 

 I have now (January 5, 1877,) before me on the microscopic slide a larva 

 of this species, just taken from the trunk of an apple tree, which is alive 

 and struggling to escape ; yet, as all are aware, we have just experienced 

 one of the coldest spells of weather ever known in this section. It is 

 proper to add, that although a part of the little colony from which this 

 was taken was living, the larger portion appeared to be dead. 



I think it is therefore evident the species may, and perhaps often does, 

 pass the entire round of the seasons, and undergo all its changes, on the 

 trunk or branches, without any transfer to the roots. Yet the root may 

 be, and probably is, its normal habitat, and the early winged females, led 

 by the mildness of the season to deposit her eggs on the trunk, the colony 

 struggles on against the cold of winter with a remarkable vitality, which 

 the species has acquired from their naturally cold habitat. So far as I am 

 aware, no difference has been discovered between those dwelling on the 

 trunk and those on the roots, though this point has not been thoroughly 

 studied. 



Natural Enemies. — It is probable that the insects which attack the 

 ordinary plant-lice will also attack with equal avidity the Woolly Aphis, 

 especially those individuals found exposed on the trunk and branches; 

 but as special enemies we may mention the following: A minute Chalcis 

 fi\ ^ Eriophilus ?nali, Hald.) has been described by Haldeman as parasitic 

 on the Woolly Aphus. A second insect enemy is the Root-louse, Syrphus 

 fly, i^Pipiza radicum, W. and R.,) first detected by Messrs. Walsh and Riley 

 as feeding on the larvae. The larvoe of this fly is a footless maggot, about 

 half an inch long, and of a dirty yellow or pale flesh color ; spindle- 



