160 APHIDS OF THE ROCKY MOUNTAIN REGION 
This species is very close to A. gossypii; indeed there seems to be no defi- 
nite distinguishing character to which exceptions cannot be found. However, 
oestlundi can generally be distinguished by the following: Longer rostral IV+-V 
(longer than .10-.11 and attaining beyond 3d coxa), smaller number and larger 
size of the sensoria on III (3-6 instead of usually 7-10) in alate vivipara, more 
uniform body color of oestlundi (lacking the mottling and variations, from dark 
green to yellow in different individuals) and absence of tessellation in the ala- 
toid nymphs, common in gossypii. A. oestlundi on Oenothera though abundant 
in the east has been, during the time studied, very rare in Colorado in spite of 
the plentiful numbers of gossypii. 
Aphis oregonensis Wilson 
Aphis oregonensis Wilson, 1915a:92; Gillette and Palmer, 1932b:426. 
Anuraphis oregonensis, Gillette and Palmer, 1928:12. 
Apterous Summer Vivipara. Dark brown to wine-red; with head, broad lateral portions 
of all segments, a pair of dorsolateral areas on metanotum and entire abdominal I covered 
with white reticulations; appendages mostly yellow; cornicle black. Body length 1.40-1.71; 
across eyes .40; hind tibia .55-.80; antenna 1.06-1.30. Hairs slightly longer than diameter of 
segment bearing them. 
Fig. 180. Aphis oregonensis 
Alate Vivipara. Body length 1.20-1.70; hind tibia .55-.85; antenna 1-1.20, secondary 
sensoria flat; rostrum with tip beyond hairs needlelike in ventral aspect, attaining abdominal 
I. Hairs spinelike, rather sparse and inconspicuous. Cauda broadly tapering, blunt, shorter 
than hind tarsal II, bearing 3 hairs on each side. Lateral tubercles developed on prothorax 
and abdominal I and VII. 
Collections. On leaves and tender twigs of Artemisia tridentata and A. 
ludoviciana subsp. typica. Colorado: Sargent, Steamboat Springs and Manassa. 
Utah: Logan, Snowville, Brigham and Honeyville. Apterous summer viviparae 
May 15 to Aug. 11, alate viviparae May 17; apparently rather rare. 
Type. U.S.N.M. Paratype, Granovsky Collection, No. 438. 
For discussion on status of the species see A. canae. 
Chief Distinguishing Characters. Brown body with reticulated pattern on 
aptera and long cornicle (.27-.45 in apterous, .17-.19 in alate vivipara). 
Aphis ornata (Gillette and Palmer) 
Anuraphis ornata Gillette and Palmer, 1929a:3. 
Aphis ornata, Gillette and Palmer, 1932b:427. 
Apterous Summer Vivipara. Head ard pronotum dusky; rest of body pale pinkish or 
flesh-color; marked by irregular dusky bands on all segments, coalescing on abdominal IV 
and V, and with dusky lateral areas; entire dorsum covered with faint white reticulations; 
appendages pale but dusky distally; cornicle, cauda and anal plate dusky to black. Body 
length 1.8; hind tibia .66-.70; antenna .80-.86; rostrum attaining 3d coxa. Hairs semierect; .02 
on antenna; .03 on hind tibia, shorter than diameter of segment bearing them. 
Alate Vivipara. Head and thorax dark brown to black; abdomen yellowish brown with 
dusky dashes on median and lateral areas of each segment; cauda and anal plate brownish to 
blackish; antenna blackish, except base of III; cornicle dusky; legs pale except femora, tarsi 
and tips of tibiae. Body length 1.5-1.9; hind tibia .66; antenna .90. Cornicle cylindrical, im- 
bricated, without distinct flange. Cauda tapering, with acute point, bearing 4-5 hairs on each 
side. Lateral tubercles present, quite large on prothorax and abdominal I and VII. Hairs as 
in apterous vivipara. 
Ovipara. Apterous. Body length 1.8; antenna .70; cauda .07; hind tibia slightly swollen 
along most of length and bearing 5-9 flat sensoria. 
