No. 115.] 125 



bein^ insoluble in water, alcohol, or solntion of potash, and is not 

 melted by the application of heat. The purpose which it serves 

 in the economy of the insect is not known. 



The allied species of woolly aphides above referred to are those 

 of the apple {Schizoneura laiiigera), of the elm [S. Rileyi)^ of the 

 oak {S. queroi)^ of the pine {S. strohi), of the hickory {S. carycp), 

 of the alder [Pemphigus tessellata)^ and a few others less frequently 

 met with. Of these the last-najned species is quite common, and 

 often occurs in great abundance, completely enveloping in its white 

 coating the branches of the alder. 



The " blue or drab-colored substance upon the leaves and ground " 

 underneath the insects, is the powdery secretion that enveloped the 

 various sized globules of excreta given out from the anal extremity 

 of the aphis, which fall to the ground " in a shower of tiny drops 

 on the slightest jar of the branch." Numbers of these little meal- 

 coated globules may be seen within the» galls of some of the gall- 

 making Peniphigina\ the coating of which prevents the fluid from 

 attaching itself to tlie plant-lice that move about freely among 

 them. 



A large portion of the white substance fastened to the under 

 surface of the beech leaf received, consisted of the cast skins 

 {exuvia) of the plant-lice at their different moltings. packed upon 

 one another in a half-dozen or more layers. 



Of course, all the aphides are injurious to the vegetation that 

 they attack — the amount of their harm depending upon their 

 numbers, and the consequent quantity of the sap that, by means of 

 their beaks inserted into the bark or leaves, they are able to 

 divert from the circulation. 



As the peculiar coating of these woolly aphides protects them 

 from most of the insecticides that could be applied to them in a 

 liquid form — shedding the fluid without absorption — perhaps 

 the best remedy for them ia crushing them with a cloth, stiff 

 brush or broom, as they occur in their conspicuous masses upon 

 the trunks and branches. 



These woolly aphides, in some localities, find a formidable enemy 

 in the larva of one of our butterflies, T^^^n^'.^eca Tarquiniuti (Fabr.). 

 The butterfly deposits her eggs upon the twigs of beech, alder, etc., 

 in the midst of a colony of the aphides. The larvje, upon hatch- 

 ing, shelter themselves beneath a thin web, and, feeding voraciously 



