2 28 DAVENPORT ACADEMY OF SCIENCES. 



tiona; terminal half of joint 3 of nearly uniform diameter, tapering 

 slightly from the upper sensorium to the base ; upper sensorial 

 membrane about one-half the length of the joint ; the lower one 

 wanting. The whole surface is densely scaly and sharply annu- 

 lated, especially the lower half. 



Phylloxera cary^-avellana Riley. 



PL v., figs. 30, 31; PI. VI., figs. 32-36 ; PI. XI., figs. 79-8i.' 



Phylloxera carycB-avellana Riley. Am. Ent., Vol. III., n. ser.. 

 Vol. I., p. 230. 



Not uncommon on the leaves of Hicoria tomentosa along the 

 Potomac near Washington. 



Judging from the appearance of the galls, as regards size, shape 

 and color, one might be led to conclude that we had to deal with 

 two ox more' distinct species. A careful study and comparison, 

 however, of the architects in their different stages, shows but one 

 species. The more typical, larger and more brilliantly colored 

 galls are the product of those stem-mothers which first settled, at 

 a time when the development of the young leaves was most rapid 

 and the circulation of the sap most vigorous. 



By the 20th of May many of the galls already contain pupae or 

 even winged females, while others contain only eggs and larvae. 

 By the middle of June most of the galls are already empty and by 

 the end of the month have become dryland shrivelled. 



The transverse diameter varies from 5-10"™- and the height is 

 about the same. Flat or but slightly convex above and either 

 flush with or somewhat sunken beneath the surface of the leaf ; 

 sub-conical or more or less globular beneath,, constricted at base 

 and resembling somewhat in shape a diminutive filbert. The sur- 

 face beneath is quite densely pubescent and with similar minute 

 yellow papillae as those which cover the under side of the leaves, 

 and causing a certain stickiness. The orifice, at the top of the 

 gall, is, before maturity, closely drawn together and densely 

 covered on the inside with white wooly hairs, opening at maturity 

 into several short and stout bracts. Walls very thick and succu- 

 lent. The color above is either greenish, yellow-^een or of a 

 more or less intense, beautiful crimson or pink ; and beneath pale 

 greenish, or even almost white. 



