PERGANDE NORTH AMERICAN PHYLLOXERINiE. 263 



his observations on the economy of Ph. vastatrix, quercus and 

 balbianii, in Comptes Rendus des Stances de ly' Academic des 

 Sciences, for 1875, p. 1223, and mentioned by him in the Stet- 

 tiner Ent. Zeitung, p. 359, 1875. According to the above it 

 seems to be justifiable to assume that the species was worked up 

 in conjunction by both gentlemen, but that the species should be 

 credited to Riley. 



While consulting Dr. Riley's description of the apterous 

 female or stem-mother of this species, p. 86, I have come to the 

 conclusion that the description of his supposed female corresponds 

 exactly with fig. 19, representing a female larva, specimens of 

 which are still preserved in the original collection, whereas the 

 mature female was described in the Seventh Report, p. 120, 

 under the designation of ' ' Black form with very long tubercles 

 (c)" — where the following language is used by him: "With 

 the body dark brown and the tubercles almost black ; the dorsal 

 ones, especially in middle of body, very long — half the diameter 

 of body — slender, gradually tapering to tip, the lateral ones and 

 some of the dorsal ones, less tapering and half as long. Antennae 

 with the third joint quite long and slender." Of this form two 

 specimens have been preserved. 



Thus far this species has been recorded as having been found 

 only on the white oak (^Q. alba) and the post-oak (g. obtusiloba) 

 in the vicinity of Kirkwood, Mo., on the leaves of which it pro- 

 duces white or yellowish circular spots; the insect, in various 

 stages of development, often in immense numbers, is, as a rule, 

 found ou the under side of the leaves, whereas the earliest forms, 

 as well as the sexes, frequent the branches, on which the winter 

 eggs are deposited. The earliest migrants are usually observed 

 during July and the latest in October. Whether the earliest 

 migrants produce a sexual generation or not has thus far not been 

 demonstrated, though it seems to be quite certain, since hibernat- 

 ing larvae, which apparently hatched from the earliest eggs, as 

 well as eggs, appear to have been found on the twigs. 



Phylloxera querceti Pergande, n. sp. 

 PI. XX., figs. 155-158. 

 Apterous female.— I/cngth about 0.5™™-; shape pyriform, 

 broadest about the middle of the thorax, rounded in front and 



