342 



INSECT ARCHITECTURE. 



harder than the latter. In this snug little chamber, secure 

 from the intrusion of lady -birds and the grabs of aphidi- 

 vorous flies (Syrphi), she brings forth her numerous brood 

 of young ones, who immediately assist in enlarging the 

 extent of their dwelling, by puncturing the walls. In one 

 respect, however, the galls thus formed differ from those of 

 the mountain-ash just described, — those of the poplar having 

 always an opening left into some part of the cell, and 

 usuall}^ in that portion of it which is elongated into an 

 obtuse beak. From this opening the young, when arrived 

 at the winged state, make their exit, to form new colonies ; 

 and, during their migrations, attract the attention of the 

 most incurious by the singularity of their appearance- 

 (J. E.) 





w '#^ ^^ 



Galls produced on the leaves and leaf-stalks of the Poplar by Eriosoma populi, with the 

 various forms of the insects, winged, not winged, and covered with wool, both of the 

 natural size and magnitied. 



On the black poplar there ma}" be found, later in the 

 season than the preceding, a gall of a very different foim, 

 though, like the other, it is for the most part on the leaf- 



