GENERIC AND SPECIFIC SYNONYMY. 7 



"Alder blight, E. tcssellata. Dull bluish-black; tergum with the 

 segments marked by strongly impressed lines and covered by white 

 down in square checker-like spots. Length, 0.16. On the underside 

 of branches of the alder {Alnus rubra, Marsh.) crowded together and 

 concealed beneath a dense covering of snow-white down. I have 

 searched in vain for winged individuals of this species. No. 863." 



A few years later Prof. S. S. Haldeman described the same species ^ 

 as a large species forming follicles on the leaves of the silver-leaved 

 maple, Acer enocarpum (of which Acer dasycarp^im is but a syn- 

 onym). He refers to it as follows: 



''''Aphis {Pemphigus) stamineus. 



" This name is projoosed for a large species of Aphis which forms 

 follicles on the leaves of the silver-leafed maple {Acer enocarpum) ^ 



Prof. Haldeman, who mistook the migratory female for the male, 

 gave the following description of the insect: 



'•'' Male. — Black, feet long, slender, and rufous; tarsi biarticulate ; 

 wings slightly deflexed, translucent, pale ferruginous at the base, 

 submarginal nervure conspicuous, black, and ending in a long stigma; 

 disk with four simple nervures ; posterior wings with three nervures ; 

 mesonotum polished, with a deep Y-shaped impression; abdomen 

 without tubes; promuscis obsolete, antenna 6-articulate, the first 

 two short, the third long, and the fourth, fifth, and sixth gradually 

 lengthening ; length of body, 1^ lines, or, to the end of the wings, 2| 

 lines. 



" Female a7id pupa. — Apterous, dark-reddish brown, feet paler ; 

 promuscis twice as long as the head, thickened near the apex ; length, 

 li lines." 



This is without a doubt the same species as the one described by 

 Prof. C. V. Riley under the name of Pemphigus acerifolii.) the de- 

 scription of which, for the benefit of those interested in this subject, 

 may be here reproduced. 



^^ Pemphigus acerifoUi Riley. 



" Living in abundant and long cottony excretions on the underside 

 of the leaves of Acer dasycarpum, causing them to curl, and exuding 

 an abundance of thick and very glutinous ' honey-dew.' 



" Winged female. — Alar expanse 16 mm. Head and thorax bluish- 

 black. Abdomen black, covered with long cottony threads. An- 

 tennae reaching the wing insertions; annulations not conspicuous; 

 joints 3, 4, 5, and 6 somewhat contracted at base and apex; apical 

 unguis not perceptible; joints 5 and 6 subequal; 4 distinctly clavate; 

 3 as long as the two preceding together. AVings subhyaline, of a 



1 Proc. Roston Soc. Nat. Hist., vol. 6, p. 403, 1859. 

 25795°— No. 24—12 2 



