204 APHIDS OF THE RoCKY MOUNTAIN REGION 
Alate Vivipara. Same in color and measurements as aptera. Secondary sensoria flat. 
Hairs on body broadly funnel-shaped with slender shaft and on slightly broadened base or 
pedicle, numerous and erect, .05 long; on antenna but slightly capitate, drooping and sparse; 
on hind tibia, blunt to pointed, drooping and .02-.03 long, longer than diameter of tibia and 
fairly numerous. Cornicle truncate or slightly mammiform, without flange, not imbricated, 
hardly more than a raised pore. Cauda tapering to parallel-sided, elongate, rather acute, bear- 
ing 3-4 hairs on each side and 2-3 dorsal ones near tip. 
Ovipara. Apterous. (Mounted in balsam), color and measurements same as in apterous 
vivipara, except as follows: Body more pointed posteriorly and hind tibia with proximal third 
to nearly half distinctly swollen, blackish, and bearing about 14 flat sensoria. 
Collections*. On leaves and flower stems of Artemisia tridentata. Colorado: 
Paonia. Utah: Throughout state. Idaho: Twin Falls. Apterous summer vivi- 
parae Aug. 24, oviparae Nov. 4; apparently rare. 
Genus Hyalopterus Koch 
Koch, 1854:16; Baker, 1920a:47. ; 
Characters. Vertex distinctly convex; frontal tubercles developed equal 
with vertex. Antenna six-segmented; secondary sensoria circular, convex. 
Hairs conspicuous, pointed. Cauda parallel-sided to elongate-tapering to spoon- 
shaped. Cornicle cylindrical to slightly clavate, without flange, with opening at 
tip not oblique. Fore wing venation as in Aphis. Lateral tubercles present. 
Genotype (fixed by Passerini, 1860), Aphis pruni Fabricius (syn. of A. arundinis 
Fabricius). 
Key to Species of Hyalopterus 
1. Rostral IV+V broad, .08 long, about half length of hind tarsal II; sensoria 
present on IV of alata. (pi: 204) 15k ae cae eee arundinis 
Rostral IV+-V not broad, .12 long, almost equalling length of hind tarsal II; 
sensoria absent on IV of alata! (ps 205) )ccccc2e ce sccees sates ee een nue ee atriplicis 
Genotype Hyalopterus arundinis (Fabricius) 
The Mealy Plum Aphid 
Aphis arundinis Fabricius, 1775:734. 
Aphis pruni Fabricius, 1775:735. 
Hyalopterus arundinis, Davidson (W. M.), 1919a:1; Theobald, 1927:19; Gillette and 
Palmer, 1932b:473. 
Fundatrix. Same as summer apterous vivipara except the following: Body length 2.10- 
2.35, width 1.30; hind tibia .60-.70; hind tarsal II .12; antenna .70-.80, III+IV (coalesced) 
.23-.34, V .13-.17, VI .09-++.13; cornicle .03. 
Oe Small Fores 
Apterous Summer Vivipara. Yellow-green with powdery areas dorsolaterally, leaving 
3 longitudinal greener lines; cornicle, cauda, and appendages pale; tarsi, tips of appendages 
dusky. Large Form. Body length 1.80-2.10; hind tibia 1.1; hind tarsal II .17; antenna 1.95-2; 
rostral IV+V broad, width at base exceeding half of length, attaining 2d coxa. Hairs .03 
long on hind tibia. Small Form. Body length 1.30-1.50; antenna 1.30-1.50; hind tibia .65-.85; 
hind tarsal II .13-.14; cauda .10 on median line, .15 on side. 
Alate Vivipara. Head and thorax brown; abdomen yellow-green to apple-green; powdery; 
appendages and cornicle slightly dusky; cauda and anal plate pale to slightly dusky. Body 
length 1.5-1.9; hind tibia 1; hind tarsal II, .15; antenna 1.4-1.8, secondary sensoria convex to 
slightly tuberculate. Hairs pointed, sparse; .02 on hind tibia. Cornicle cylindrical to slightly 
clavate, weak, without flange, not imbricated. Cauda parallel-sided to elongate-tapering with 
rather abruptly broadened base, suggesting slight neck, bearing 2-3 pairs of lateral hairs and 
a single preapical one. Lateral tubercles present on prothorax and all abdominal segments. 
*Alate viviparae used in description were presented to our collection by H. F. Wilson, 
collected at Hermiston, Oregon May 2, 1914. Oviparae were presented by Ralph H. 
Smith from Idaho. 
