326 APHIDS OF THE ROCKY MOUNTAIN REGION 
This species has been declared synonymous with M. gei (Koch) by Theo- 
bald (op. cit.) but is considered distinct by. Hille Ris Lambers (1939:83), with 
differences as follows: (Fewer caudal hairs (fewer than 12), length of unguis in 
summer viviparae (longer than III), length of tibial hairs (shorter than .07-.10) 
and appendages lighter in color (not blackish and not dusky). 
Opinion as to synonymy was aided by study of specimens of M. gei deter- 
mined by Hille Ris Lambers. 
Macrosiphum sonchellum (Monell) 
(Plate IV, 1-2) 
Siphonophora sonchella Monell, 1879:21; Williams, 1910:83, 
Siphonophora muralis Buckton (misidentification) ; Davis, 1911b:31; Theobald, 1926: 
93 (discussion of status). 
Macrosiphum williamsi Gillette and Palmer, 1929:468. 
Macrosiphum sonchellum, Gillette and Palmer, 1934:196. 
Apterous Summer Vivipara. Deep brownish red to brick-red, yellowish on head, pronotum 
and abdominal VIII; shining; tibiae, cauda and anal plate yellow; cornicle black; antenna 
dusky after base of III; knees, tips of tibiae and entire tarsi black. Body length 2-2.5; across 
eyes .48; hind tibia 1.66-2; hind tarsal II .16-.18; antenna 2.5-3.4; rostrum surpassing 2d coxa. 
Hairs blunt to slightly capitate; on side of abdomen .03-.04. Cauda tapering ending in rather 
acute point, bearing about 6-7 lateral and dorsolateral hairs on each side, and a dorsal 
preapical one; several of the terminal ones sometimes approximately straight and capitate. 
Alate Vivipara. Head and thorax pale red. Otherwise same as apterous vivipara except 
differences as shown in figure. 
yas 1 ee FOO Sec ae 05 0°,0%5, > oe we S Coe Posy (75-88) 
(pn l/2) ROG nN) (32-38)  (.30-.35) 
Be BRATS not RR CERO A 
Cj10=0394) (sen. 9/) 
Alate eee = i Ge Bae 
Hd paemeoares: " ESE a, Apt. Vins, Ci TEER) i 
Fig. 390. Macrosiphum sonchellum 
Collections. On leaves and stems of wild lettuce (Lactuca sp.). Colorado: 
Masonville and Fort Collins. Apterous summer viviparae May 30 and July 6, 
alate viviparae May 30 and June 2; rare. 
Type. Davis collection. M. williamsi U.S.N.M., No. 41924. 
Chief Distinguishing Characters. Red body with yellow legs and cauda and 
black cornicle, numerous tuberculate sensoria on III in both alate and apterous 
viviparae and their presence on IV in alate and occasionally in apterous vivi- 
para, short IV (only third length of III), short unguis (shorter than III), rather 
short rostral IV+V (hardly as long as hind tarsal II), length of cornicle (less 
than half of III) and short many-haired cauda. 
Macrosiphum taraxaci (Kaltenbach) 
The Dark Dandelion Aphid 
Aphis taraxaci Kaltenbach, 1843:30. 
Macrosiphum taraxacl, Theobald, 1926:97; Gillette and Palmer, 1934:197. 
Fundatrix. Same as apterous summer vivipara except as follows: Body length about 2; 
hind tibia 1.2-1.5; antenna 2; cornicle .50-.55. 
Apterous Summer Vivipara. Dark rusty brown, with large dusky areas at bases of hairs; 
cornicle, cauda, anal plate and appendages except bases of femora black. Body length 2.5-3; 
across eyes .50-.57; hind tibia 1.95-2.1 antenna 2.3-3.1; rostrum attaining 3d coxa. Hairs slightly 
capitate; on hind tibia .06-.08; on side of abdomen .05. Cornicle heavy, diameter at middle 
exceeding that of hind tibia. Cauda broad, tapering to slightly spatulate, bearing about 2-4 
pairs of lateral and 1 dorsolateral pairs of hairs and a single dorsal preapical one. 
Alate Vivipara. Head and thorax black; abdomen deep reddish brown, or appearing deep 
black to naked eye; all appendages including rostrum and anal plate black. Same in measure- 
