306 APHIDS OF THE ROCKY MOUNTAIN REGION 
Macrosiphum flavilum (Knowlton and Allen) n. comb. 
Mucrotrichaphis flavila Knowlton and Allen, 1940:35. 
Alate Vivipara. “Dark.” (Cleared and mounted), head and thorax dark; abdomen with 
dark areas at bases of hairs, especially dorsolaterally, which tend to coalesce; entire antenna 
except base of III, legs, cornicle, cauda, anal plate and rostrum dark. Body length 2.1-2.3; 
across eyes .50; antenna 3.07-3.2; hind tibia 1.50; rostrum attaining 2d coxa. Hairs pointed to 
blunt. Cornicle bearing 5-8 hairs. Cauda slender, spatulate to parallel-sided, bearing about 
5 pairs of lateral and dorsolateral hairs. 
Fig. 363. Macrosiphum flavilum 
Collections. On Artemisia sp. Wyoming: Yellowstone National Park. Idaho: 
Montpelier. Alate viviparae July 18 and 19; rare. 
Type. U.S.N.M. or Knowlton Collection. 
Chief Distinguishing Characters. Long antenna, especially unguis (.90-1) 
and large number of sensoria (20-28) on III of alate vivipara. 
Macrosiphum frigidae (Oestlund) 
Nectarophora frigidae Oestlund, 1887 :83. 
Macrosiphum frigidae, Essig, 191lc: 546; Gillette and Palmer, 1928:6 and 1934:179; 
Knowlton and Allen, 1938c:80. 
Apterous Summer Vivipara. Dark metallic green, shining; dark specks at dorsal hair 
bases; cauda dusky; antenna black beyond base of III; tibiae dusky yellow to blackish; 
cornicle black. (Cleared and mounted), cornicle, cauda, anal plate, entire legs except bases 
of femora, entire rostrum and antenna except base of III blackish; head and subgenital plate 
dusky; areas at bases of dorsal hairs usually pale dusky also a lateral row of black spots each 
adjacent to a spiracle and 2 dorsolateral rows of spots. Body length 2; across eyes .45-.55; 
hind tibia 1.3-1.5; hind tarsal II .15-.17; antenna 2.3-2.7; rostrum attaining 3d coxa. Hairs 
slightly capitate; hind tibia .05-.06; on side of abdomen .06. Cauda spatulate, bearing 4 pairs 
of lateral and 2 single dorsal preapical hairs. Cornicle usually with about 2 hairs; reticulated 
area .08. 
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Fig: 364, Maieselsnen Finidae 
Alate Vivipara. Head and thorax black; otherwise same as apterous vivipara except as 
follows: Dark areas at bases of dorsal hairs hardly evident in cleared specimens; antenna 
2.5-2.9; rostrum not surpassing 2d coxa; hairs on hind tibia .04-.05. 
Ovipara. Apterous. Color same as in apterous vivipara or more brownish or olive-green. 
Body length 2; antenna 1.9-2.3; cornicle .25-.32; cauda .18-.20 on median line, .25-.28 on side; 
hind tibia with proximal half swollen to about twice diameter of narrowest»portion and 
bearing numerous sensoria. 
| Male. Apterous. Dark olive-green or brown; legs dusky yellowish; antenna, cornicle and 
cauda black. Body length 1.4; antenna about 1.8-2; hind tibia 1.2; cornicle .22, reticulated 
area .05 and in appearance approaching imbrication; cauda .10-.13 on median line, .15-.18 on 
side. 
