A SYNOPSIS OF THE APHID TRIBE PTEROCOMMINI. 
By H. F. Wirson, 
Entomologist, Oregon Agricultural College. 
As in all other groups of the Hemipterous family A phidide 
the species grouped under the tribe name Pterocommini have 
been greatly mixed by different writers and as a result much 
confusion exists. In this paper the writer hopes to eliminate 
at least a part of this. 
All the known species commonly feed on willows and 
poplars; one species is recorded as also being found on maple. 
Three species (P. salicis, populea and flocculosum) are recorded 
from Europe and five from America (P. populea, smithie, 
flocculosum, bicolor and salicis). The writer has never found 
the last nor has he seen specimens collected in this country. 
In all ten species have been described as follows: 
1758 Pterocomma (A phis) salicts Linn. 
1843 Pterocomma (A phis) populea Kaltenback. 
1879 Pterocomma pilosa Buckton. 
1842 Pterocomma (Aphis) salictt Harris. 
1862 Pterocomma (Lachnus salicola) Uhler. New name for A phis salictt. 
1879 Pterocomma (Chaitophorus) smithie Monell. 
1887 Pterocomma (Melanoxanthus) flocculosus. Weed. 
1891 Pteracomma (Cladobius) beuhahensis cockerell. 
1909 Pterocomma (Cladobius rufulus Davidson. 
1910 Cladobius lanthane Pass (Koch) Henrich. 
Generic Synonomy. 
Aphidologists in general have divided the species of this 
tribe into two groups based as a rule upon the structure of the 
nectaries, although Buckton erected the genus Pterocomma 
for his species P. pilosa on what he thought was a peculiar 
wing structure. (Pergande* believes this apparent character 
due to a fold in the wing.) Those species having swollen 
nectaries have been placed in one genus and those having 
cylindrical nectaries were placed in another. Such a distinction 
was also made by the writer in 1909, but after having further 
studied the group I am of the opinion that such a division is 
illogical and if a division is necessary each species should form 
a different genus. It, therefore, seems more practical to 
confine all the species to a single genus. 
The genus name Cladobius found by Koch, 1857, was pre- 
viously used in Coleoptera, 1837. Passerini, 1860, suggested a 
new name, Aphioides, but the writer believes that this 1s a 
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