98 APHIDS OF THE ROCKY MOUNTAIN REGION 
Chief Distinguishing Characters. Length of unguis (4-5.5 times base of 
VI), long hairs (about .20 long on hind tibia) and number of sensoria on III of 
alate vivipara (about 10). 
Periphyllus macrostachyae (Essig) 
Symydobius macrostachyae Essig, 1912a:727. 
Periphyllus macrostachyae, Gillette and Palmer, 1931:922. 
Apterous Summer Vivipara. Reddish brown to blackish; with lighter area about cornicles 
and often paler Y or V marking on dorsum of abdomen; legs pale brownish with knees, tips of 
tibiae and tarsi dusky to blackish; cornicle yellow. Body 1.5-2 by .8-1.0; hind tibia .7-.8; hind 
tarsal II .12-.14; antenna .75-1.0. Nymph. Pale or reddish yellow marked by reddish brown 
as follows: Band on abdominal I, a pair of dorsolateral longitudinal lines from prothorax to 
abdominal IV, and ring enclosing pale area around each cornicle and connecting anteriorly 
with band on abdominal I, thus making pale Y or V pattern on dorsum, similar to P. populi- 
cola. 
Alate Vivipara. Head and thorax dark; abdomen reddish brown with black bands; fore 
wing slightly smoky, veins narrowly bordered with brown, stigma short with depression at 
distal end and with light streak extending from subcosta. Posterior edge of stigma bearing 
scattered setulae. Body length 1.5-2.5 long; hind tibia 1.0; hind tarsal II .16; antenna 1.3. 
Hairs on body of two kinds, some heavy spinelike, .07-.10 long and rather sparse and others 
finer spinelike .04 long, numerous; on vertex .05-.08; on antenna fine; on hind tibia fine, 
.03-.04, erect. Rostral IV-+V .18-.20 long attaining abdominal ITI or III. 
Ovipara. Apterous. Body rather elongate, length 1.60-2; hind tibia moderately swollen 
and bearing scattered sensoria over most of length. 
Male. Apterous. Body length .75-.90; hind tibia .50; hind tarsal II .10; antenna .65. 
= SS 3 SiArt) .20 
Fig. 106. Periphyllus macrostachyae 
Collections. On bark of twigs of Salix sp. Colorado: Fort Collins, Bellvue, 
Boulder, Rocky Ford and Englewood. Utah: Bear River City and Currant 
Creek. Apterous viviparae May 2 to Aug. 21, alate viviparae May 9 to Aug. 21, 
oviparae Oct. 14 to 25, males Oct. 14; rather common. 
Type. Essig Collection, No. 50. 
This form differs from P. macrostachyae in the shorter rostrum which 
attains abdominal II (according to the original description “beyond tip of ab- 
domen,” but in two paratypes examined attaining middle of abdomen). How- 
ever, as no other specific differences are apparent and the rostrum has been 
suspected of possible retractibility there seems to be insufficient basis for 
formation of a new species at this time. 
Periphyllus negundinis (Thomas) 
The Boxelder Aphid 
Chaitophorus negundinis Thomas, 1877:10; Cockerell, 1904:263; Davis, 1908a:130 and 
1910b:14; Webster, 1917:95; Baker, 1918:87. 
Periphyllus negundinis, Gillette and Palmer, 1931:923. 
Fundatrix. Rather dark apple-green; antenna pale to tip of V, remainder blackish; legs 
pale except tarsi and tips of tibiae. Body length 2.5-2.9; antenna .90-1.0, sometimes five-seg- 
mented; hind tibia .90. Otherwise as in apterous summer vivipara. 
Apterous Summer Vivipara. Yellowish or sap-green to apple-green, with a pair of darker 
green vittae; legs pale to dusky; cornicle pale; antenna pale except tip. Body 2.0-2.5 by 1.0; 
hind tibia .70-1.1; hind tarsal II .15; antenna 1.0-1.5. Hairs heavy, spine-like and numerous, 
-15 long on vertex, .12 on body; slender and spinelike on appendages, on antennal III .05-.09, 
on hind tibia .05-.12. 
