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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, are intended by nature to come to the 
open air with the power to roam and seek new localities. It is sup¬ 
posed by some that those on the trunk and branches remove to the 
roots as winter approaches. I have strong doubts on this point, un¬ 
less by “removing, 5 ’ is meant that the mature winged females, which 
appear among these colonies at the approach of winter, after pairing, 
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 December 11, after two snow storms and many cold rains and 
freezing nights. 1 have now, January 5, 1877, before me on the mi¬ 
croscopic 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 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 their eggs on the 
trunks, the colony struggles on against the cold of winter with a re¬ 
markable vitality, which the species has acquired from its naturally 
cold habitat. So far as I am atvare, no difference has been discovered 
between those dwelling on the trunk, arid tnose 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 Wooly Aphis, 
especially those individuals found exposed on the trunk and branches; 
but as special enemies we may mention the following: A minute 
Chalcis fly ( Eriophilus mall, Ilald). has been described by Halder- 
man as parasitic on the Wooly Aphis. A second insect enemy is the 
Root-louse Syrphus-fly ( Pipiza radicum, W&R.,) first detected by 
Messrs. Walsh and Riley, as feeding on the larvae. The larva ot 
this fly is a footless maggot, about half an inch long, and of a dirty 
yellow or pale flesh color; spindle-shaped, attenuated in front and 
somewhat more abruptly lessened behind; the body is marked with 
transverse ridges. When not extended, its length is only about one- 
Fig. 20.-Root Louse Syrphus Fly. a, Larva, b , Pupa, c, Perfect Fly. 
fourth of an inch. A third enemy is a minute lady-bird, only about 
one-twentieth of an inch long, and of a deep brown color on the wing- 
