292 APHIDS OF THE ROCKY MOUNTAIN REGION 
Male. Alate. Head and thorax dark greenish brown; abdomen olive-green; cornicle and 
appendages except base of antennal III, blackish; cauda pale. Body length 2.15; hind tibia 2; 
antenna 3.25; cornicle .35-.40, reticulated area .10 long. 
Egg. Newly laid, amber-yellow, tinged with greenish; later, black. Size .80 by .40. 
Collections. On leaves and tender stems of Ambrosia trifida, Chrysotham- 
nus nauseosus subsp. nauseosus, Iva xanthifolia, Rudbeckia sp. and occasion- 
ally Helianthus sp. Throughout region. Apterous summer viviparae May 22 to 
Oct, 23, alate viviparae May 30 to Oct. 23, sexuales Sept. 15 to Nov. 9; very 
common and abundant. 
Red Color Variety: 
This aphid differing only in the brick to blood-red body, seems structurally 
indistinguishable from M. ambrosiae. It differs slightly from M. solidaginis 
(Fabricius) according to van der Goot (1915:90) as follows: Legs not yellow, 
cauda not black, sensoria more numerous and not distributed along entire II in 
aptera, cornicle stouter and reticulated on distal third instead of one-sixth (as 
in figure by Theobald, 1926:98) and possible differences in ratios in antennal 
segments. Theobald (1926:100) states that the American form, according to 
Williams (op. cit.) seems not to be the European species. However, he does not © 
state the differences and describes the sensoria in aptera as similar to our form. 
a | 
(60-.80) aa 
(80S- peu 
eT 
90-~1.07) 
Fig. 346. Macrosiphum ambrosiae 
From M. rudbeckiae this form differs as follows: Darker blood-red color of 
body, presence of dusky hair bases on dorsum of abdomen, especially in aptera 
and lack of pale base on cornicle. It appears to be near M. lanceolatum Patch, 
but type specimens of the latter are not available at this time for comparison. 
Until biological transfer tests determine the relation between these forms it 
seems best to leave the form on Solidago here rather than erect a new species 
on such slight and possibly unstable differences. 
Collections. On leaves and stems of Solidago sp., Lactuca sp. and Aster sp. 
Colorado: Fort Collins, Loveland, Willow Creek (Custer Co.), Hotchkiss and 
Rocky Mountain National Park. New Mexico: Pecos. Idaho: Twin Falls. Ap- 
terous viviparae May 30 to Oct. 27, Nov. 4, alate viviparae May 30 to Oct. 8; 
rather common. 
_ Lectotype. Ill. Nat. Hist. Surv. Collection, No. 8179 also paratypes, Nos. 
8180 and 8181. 
Chief Distinguishing Characters. Dark areas at dorsal hair bases, especially 
prominent in aptera, pale cauda, entirely black cornicle, typically sepia-brown 
body, long reticulated portion (about .30) on long cornicle (.80-.95), numerous 
tuberculate sensoria on III (31-45 in alate and 14-27 in apterous vivipara) and 
long cauda (about .60), bearing about 7 hairs on each side. 
Macrosiphum anomellum Knowlton and Allen n. comb. 
Macrosiphum anomellus (sic.) Knowlton and Allen, 1938¢:75. 
Mucrotrichaphis anomellus Knowlton and Allen, 1940:34. 
Apterous Summer Vivipara. (Cleared and mounted), head dark; abdomen colorless with 
faint dark areas at the bases of the numerous pointed hairs on dorsum; antenna except prox- 
imal portion of III, cornicle, cauda, anal plate, rostrum and legs, especially knees and distal 
