104 APHIDS OF THE ROCKY MOUNTAIN REGION 
black speckles, each bearing a pale hair. Surface roughened by scattered denticles. Antenna 
and cornicle blackish; tibiae, cauda, anal plate and tip of rostrum dusky. Antenna either five- 
or six-segmented; about .75 long. Wings hyaline; stigma greenish, media usually twice- 
forked but very variable, sometimes once-forked. Body length about 1.90; across eyes .45; 
hind tibia .62. Hairs heavy, spinelike and numerous; .0® long on body and vertex; on antenna 
and hind tibia as in Hea vivipara. 
i= 12H alse 
7 Fig. 112. Sipha glyceriae 
Hosts. On leaves of the following grasses: Glyceria fluitans, Juncus 
lampocarpus, Phalaris arundinacea, Poa annua and others. Dropping off and 
feigning death when disturbed. (Not reported from region.) 
Data for above description and figures taken from specimens determined 
by Hille Ris Lambers. 
Subtribe Pterocommina Baker 
Baker, 1920a:35. 
Characters. Prominent hairs on body and appendages. Frontal tubercles un- 
developed. Lateral tubercles well developed. Ocular tubercle present. Cornicle 
more or less elongate; cylindrical or clavate. Cauda semilunar; anal plate entire. 
Gonophophyses 3. Living on bark of trees. 
This group shows the following affinities to Aphini in which group it has 
been placed by van der Goot: Three gonopophyses and elongate cornicle. The 
following characters agree with Chaitophorina: Hairiness of body and ap- 
pendages, shape. of cauda and anal plate (similar to Periphyllus) and frontal 
tubercles. The following characters disagree: Shape of cornicle and number of 
gonopophyses (4 in Chaitophorina). The Drepanosiphina also exhibit 3 gono- 
pophyses, and elongate cornicles. It seems best to leave the group under the 
Panaphini. 
Genus Pterocomma Buckton 
Pterocomma Buckton, 1879:142; Baker, 1920a:36. 
Plocamaphis Oestlund, 1922:122. 
Characters. Cornicle elongate (in braggii minute) with distinct flange 
(except in braggii and flocculosa). Antenna shorter than body, bearing pointed 
hairs as long to longer than diameter of segments bearing them. Cauda semi- 
lunar; anal plate entire. Body and appendages conspicuously hairy. Lateral 
and ocular tubercles well developed. Living on bark of Salix and Populus. 
Genotype (monotypical), Pterocomma pilosa Buckton. 
Key to Species of Pterocomma 
1. -Cornicle uniformly. ‘cy ]imd ri cake eter cece as ceo eae 8 
Cornicle often-or al ways swollen ce oseoo researc 2 
2. Cornicle sometimes swollen and sometimes cylindrical; unguis longer 
than ‘cornicle: (ps: 105). sec ee fee ere ne ce ee ee eee ee ee beulahensis 
Cornicle always swollen; unguis not longer than cornicle (except in 
Bragg1t and pil Osa ) scsescccssoses sissies ee ea Lc pL 3 
3; ‘Cornicle ‘with flangei2.a. 222 ee ee eee ee 4 
Cotnicle: without. flange sc. 25incc Riise cce tic en te tactic a rai eo ge 7 
4. Cornicle distinctly more than twice as long as wide; proximal one-fourth 
not? swollents.f0.23. S628 cc Ee Se ee eee ee 5 
Cornicle about twice as long as wide, swelling beginning at base >: 110) fanart smithiae 
5. Cornicle at middle swollen to twice diameter at base; bright orange (p. 109)...........- salicis 
Cornicle swollen less than 1.5 times diameter at base; not bright orange................--:s.:-s00= 6 
