19(M» ENTOMOLOGICAL SOCIETY. 63 



Eriophyes sp. This is one of the ''frosts" produced by the work of the 

 mite upon the leaves. The patches of frost are pur© white in color, and 

 occur on the under side of the leaves, in the axils of the veins. Under the 

 microscope, these patches of "frost" appear as dense masses of thick trans- 

 parently white hairs. The patches vary in size from 4-10 m.m. On the 

 leaves of Alnus incana. Not common. 



Eriophyes sp. This consists of a dense mat of brown hairs growing in 

 large patches upon the under sides of the leaves. Above, the leaf appears 

 lighter in color and rather abnormally shiny where the gall mites are work- 

 ing beneath. On Quercus coccinea. Common. 



Eriophyes sp. Circular, flat, or slightly convex patches varying from 

 2-3 m.m. in diameter on the upper side of the leaf, the under side being 

 covered with minute granular excrescences, which vary from whit-e to dark 

 brown in color. On Populus grandidentata. Common. 



Eriophyes sp. Irregular patches of frost, transparently white in color 

 and appearing as a mass of minute granules. Under the microscope similar 

 to the frost upon the Beech and Maple. Occurring upon the surface of the 

 leaves. Occurring upon the leaves of the Low Birch (Betula puTuila). Un- 

 common. 



Eriophyes sp. Similar to the above but rosy pink in color, and occurring 

 in much larger patches, upon the upper side of the leaves. On Betula lenta. 

 Common. 



Eriophyes sp. These galls are produced upon the Soft Elm, and when 

 young bear §pme resemblance to' the typical mite gall of the Elm (Eriophyes 

 ulTni), but the distinguishing peculiarity of these galls is that they grow 

 until they reach a size far exceeding that of any E. ulmi yet observed, some- 

 times attaining a length of 2 by 1.5 cm. The development of the galls 

 also differs from that of E. ulTni, which commences as a button with a con- 

 stricted neck, while this gall often commences as a Tione, or deep dimple. 

 On Red Elm (Ulmus puhescens). Not common. 



Hemiptera. 

 Spruce Gall-louse (Chermes abietis). 



These galls are greenish swellings, occurring on the twigs of various 

 species of Spruce and sometimes in immense numbers. The galls are poly- 

 thalamous, containing from three to thirty cavities within each of which 

 live twenty or thirty minute yellowish insects. In July the galls dry up, 

 and the cavities open, allowing the lice to escape. These molt and some of 

 them assume wings. This gall-louse is one of the worst pests of Spruce 

 trees known. In many parts of Ontario nearly every tree is abundantly 

 covered with this gall, and the insects do great damage by sucking the 

 juices of the tree. Occurs on White, Black and Norway Spruce — Picea alba, 

 Picea nigra and Picea excelsa. Yery common. 



Vagabond Gall (Pemphigus vagabundus). 



Produces large irregular galls on the tips of the twigs. It is a mon- 

 othalamous gall consisting of a double lamina, and between these two 

 layers are large numbers of aphids. The gall usually remains on the tree 

 over winter. Occurs on the Cottonwood (Populus deltoides). Common. 



Cochscomb Gall orh Elm (Colopha ulmicola Fitch). 



A hollow, cockscomb, thin-walled gall on the leaf x)f the American 

 Elm. Occurs on the upper side of the leaf. The apex of the gall is ser- 

 rated and the sides grooved. The gall appears inflated. The opening is 

 on the under side of the leaf, running the full length of the gall. The in- 



