222 APHIDS OF THE ROCKY MOUNTAIN REGION 
Collections. On Chrysanthemum in greenhouse and on Artemisia ludo- 
viciana and A. vulgaris*. Colorado: Fort Collins. Utah: Logan and Salt Lake 
City. Apterous and alate viviparae Oct. 12 to March 10; fairly common. 
The genus Coloradoa was erected by Wilson (1910:323) for this species but 
the characters, in the opinion of the writer, are not of generic rank. Specimens 
determined by Hille Ris Lambers as Coloradoa artemisiae (Del Guercio) appear 
identical with Wilson’s species. 
Chief Distinguishing Characters. Rudimentary frontal tubercles, imbricated 
femora, acute but not quite needlelike rostral IV+-V and shape of cornicle 
(cylindrical in proximal portion and slightly to moderately swollen in distal 
half). 
Rhopalosiphum scirpifolii Gillette and Palmer 
Rhopalosiphum scirpifolii Gillette and Palmer, 1932a:138 and 1932b:490. 
Apterous Summer Vivipara. Nymph. Dark olive-green to light green with orange stain 
between cornicles. Adu/Jt. Dark brown to greenish black, lighter laterally and anteriorly, 
sometimes orange spot at cornicle base; appendages, cornicle and cauda sordid to dusky, with 
black distally. Body length 2-2.25; hind tibia .85-1; hind tarsal II .13; antenna 1.10-1.25. 
see 13-24 43-24 
en, 16-24 
nae 260. Rhopalosiphum scirpifolii 
Alate Vivipara. Head and thorax black; abdomen greenish black; antenna and cornicle 
black; legs and rostrum dusky; cauda and anal plate dusky. Body length 1.8-2; hind tibia 
.90-1.1; hind tarsal II .12; antenna 1.2-1.6; rostrum obtuse attaining 2d coxa more or less. 
Vertex distinctly covex; frontal tubercles developed about equal to vertex. Cornicle slightly 
incrassate with large flange, faintly imbricated, slightly wider than hind tibia. Cauda 
parallel-sided with slight tendency to constriction, blunt, bearing 2 hairs on each side and one 
preapical one. Hairs pointed; sparse on antenna; rather numerous on hind tibia. Lateral 
tubercles small, present on prothorax, and abdominal I and VII. Fore wing with 2d fork of 
media short, arising at quarter to third the distance from margin of wing to Ist fork. 
Ovipara. Apterous. Color same as in apterous summer vivipara. Body length 1.50; hind 
tibia .50; antenna .65-.70. Hind tibia slightly swollen for most of length and covered with 
rather large, flat, round sensoria. 
Male. Alate. Color and measurements same as alate vivipara except body length 1.30- 
1.50. 
Egg. Newly laid, orange-yellow; later, black. 
Collections. On leaves and stems of Prunus besseyi as winter host; on 
Scirpus campestris and S. sp. as summer host. Colorado: Fort Collins. Idaho: 
Blue Gulch. Apterous summer viviparae Sept. 26 to Oct. 29, alate viviparae Oct. 
15 to 26, oviparae on P. besseyi Nov. 4, males on Scirpus and Prunus Oct. 7 to 
Nov. 2; apparently rare. 
Type. U.S.N.M., No. 43848. Paratypes, Colo. Agr. Exp. Sta. Collection. 
*The specimens taken on this plant (5 apterous and 3 alate viviparae) were smaller 
than the above-described examples, as follows: Aptera.—Body length .90-1.20; antenna 
.55-.65, III .12-.15, IV .08-.10, V .09, VI .09-.15; hind tibia .40-.50; hind tarsal II.07- .08; 
cornicle .22- .26; rostral IVtV .09, acute, attaining between 2d and 3d coxae. Alata.— 
Body length 1. io; hind tibia .60; hind tarsal II .09; antenna .85, III .24, IV .12, V .11, 
VI/.12-+.18; cornicle 24, Other characters were identical with form on Chrysanthe- 
mum, 
