142 APHIDS OF THE ROCKY MOUNTAIN REGION 
Collections. On leaves and bark of twigs of Cornus stolonifera as winter 
host, on leaves of the following as summer hosts: Amaranthus retroflexus, 
Ambrosia trifida and A. artemisiaefolia, Asclepias sp., Cirsium sp., Helianthus 
annuus and H. petiolaris, Iva xanthifolia, Mirabilis linearis and M. nyctaginea 
and Urtica gracilis. Throughout region. Fundatrices March 30 to May 6-on 
winter host, apterous summer viviparae June 4 to Nov. 9 on summer hosts, 
alate viviparae on winter host April 19 to May 30 and Aug. 8 to Oct. 1, on 
summer hosts June 4 to Nov. 9, oviparae on winter host Sept. 6 to Oct. 24, 
alate males on both winter and summer hosts Sept. 15 to Oct. 24; slightly 
curling young leaves on Cornus in spring but no tendency to curl later either 
on summer hosts or Cornus in fall; very common. 
Cotypes. Davis Collection. 
The determination of this form is based on metatypes and detailed notes 
from Monell received in correspondence. He also determined Colorado speci- 
mens sent to him as his species. 
The statements in original description that antennal III is “as long as the 
preceding taken together” and “nectaries...... less than twice the length of the 
tarsi” are evidently errors as they differ from characters found in over a dozen 
metatypes and notes received from Monell. “Preceding” may be an error for 
succeeding and the cornicle of spring migrant, shorter than in later generations, 
may fail to equal twice tarsi. Gillette’s statement (1910:405) that blackish patch 
at cornicle is absent in Monell’s species is not valid as a distinction since this 
spot is not uniformly evident in the Colorado mounts. 
A. oxybaphi Oestlund appears to be structurally inseparable fbi A. 
helianthi, differing only in the yellow color and perhaps averaging a little 
larger in size. Several years work in experimental transfers by Gillette and 
Bragg have demonstrated that this form thrives equally well either on Heli- 
anthus or Oxybaphus. In exchange of host the yellow color appears in most of 
the individuals after several generations on Oxybaphus and the green similarly 
on Helianthus. Individuals from both hosts take equally well to Cornus as 
winter host. A. oxybaphi Oestlund is accordingly placed as a synonym of A. 
helianthi. 
A. yuccae Cowen appears structurally identical with A. oxybaphi. Experi- 
mental transfers by Gillette and Bragg, though not as extensively carried out 
as in the case of A. oxybaphi, seem to indicate that A. yuccae is at least a form 
of A. helianthi. 
Aphis helichrysi Kaltenbach 
The Leaf-curl Plum Aphid (Plate VII) 
Aphis helichrysi Kaltenbach, 1843:102; Theobald, 1927:245; Smith (R.H.), 1921:422; 
Gillette and Palmer, 1932b:404 (desc. of sexuales erroneous) and 1936b:736. 
Anuraphis padi (Linnaeus), Theobald, 1927:403 (disputed synonymy). 
Aphis marutae Oestlund, Gillette and Palmer, 1936b:736 and 747 (det. of sexuales 
erroneous). 
Fundatrix. Body length 2.30; antenna .53, five-segmented; hind tibia .50-.65. 
Apterous Summer Vivipara. (On plum.) Pale green to lemon-yellow; shining; all ap- 
pendages pale. Body length 1.1-1.3; hind tibia .50-.70; antenna .60-.80. Dorsal surface of body 
granular. Lateral tubercles minute. Rostrum surpassing 2d coxa. Cauda elongate-rounded 
to bluntly tapering, bearing 2-3 pairs of lateral hairs and one preapical one. 
Alate Vivipara. Spring Migrant. Head and thorax black; abdomen green with dusky to 
glossy black dorsal patch on abdominal III or IV to tip of abdomen and dusky to black lateral 
areas on abdominal II, III and IV; cornicle pale to black; antenna blackish; tibiae brownish; 
cauda and anal plate pale. Body length 1.10-1.30; hind tibia .73-.96; antenna 1.15. Rostrum 
attaining 2d coxa. 
Ovipara. Apterous. Body length .90; antenna .40, III and IV coalesced; hind tibia .30, 
conspicuously swollen and bearing numerous sensoria. 
