268 APHIDS OF THE ROCKY MOUNTAIN REGION 
This species is very close to C. feragaeus but differs in points 1, 2 and 5, 
above. These differences are slight and doubtful, especially on account of the 
small number of the latter which have been observed. The settlement of the 
status of this species awaits the collection of more specimens, especially more 
life cycle forms of the latter. 
Capitophorus quadritrichus Knowlton and Smith 
Capitophorus quadritrichus Knowlton and Smith, 1936e:233. 
Apterous Summer Vivipara. ‘‘Bluish green, appearing grayish’; antennal I and II and 
beyond proximal half of IV, coxae, femora, knees, tips of tibiae, tarsi, rostral III and IV+V, 
and cornicle black or blackish; cauda and anal and genital plates dusky; tibiae pale. Body 
length 1.10-1.8; across eyes .37-.42; antenna 1.45-2.20; hind tibia .85-1.30-‘'1.40”; rostrum acute 
with needlelike tip in ventral aspect, attaining or surpassing 3d coxa. Hairs on vertex flat- 
tened or narrow funnel-shaped with stalk; on antennal I and II blunt to slightly globate and 
inconspicuous; on III blunt, short and sparse; on body funnel-shaped, with slight stalk or 
sessile, numerous; on hind tibia slightly globate, fairly numerous. Cornicle slightly clavate, 
slender. Cauda spatulate, bearing 2 pairs of lateral hairs and a single dorsal preapical one. 
Alate Vivipara. Color and measurements same as in apterous summer vivipara except 
appendages which are darker with paler portions dusky and hairs somewhat shorter. 
Apt. Viu REL ARBEA DED AT PEE 
Ir, AB-"52" Sen, 1-2 -25 -40-"47" 25-agtAn" = 
OS) 05) (Coe sre 
x a + 47 = 6 2% 
" 22-40 «Aptst!-!+ 
edy Hairs 30-"33"eAlate+ 19-4 74 
aslib, 
a a eee ea! 
30” Sen. 
Fig. 321. Capitophorus quadritrichus 
Collections. On Artemisia tridentata. Utah: Throughout state. Apterous 
viviparae May 17 to Aug. 26, alate viviparae June 9 and July 5; not rare. 
Type and Paratypes. Knowlton Collection. Paratypes also in Colo. Agr. 
Exp. Sta. Collection. 
Chief Distinguishing Characters. Pale green body and dark appendages, 
length of antenna (exceeding that of body), length of rostral IV+V (not ex- 
ceeding .16), the short cornicle (shorter than IV or V). character of hairs on 
I and II (slightly globate, short and reclinate), needlelike tip of rostrum and 
spatulate cauda, bearing only 2 pairs of lateral hairs. 
Capitophorus ribis (Linnaeus) 
The Currant Aphid 
Aphis ribis Linnaeus, 1758:451. 
Myzus ribis, Gillette and Bragg, 1917b:338. 
Capitophorus ribis, Theobald, 1926:229; Gillette and Palmer, 1934:155. 
Apterous Summer Vivipara. Pale greenish yellow; cauda, anal plate and cornicle pale; 
antenna pale except tips of segments; tibiae pale to brownish. Body length 1.60-1.80; across 
eyes .44; hind tibia 1.40-1.55; hind tarsal II .10; antenna 2.60; rostrum obtuse, attaining 3d 
coxa. Hairs capitate with slender stalk and globate Here on vertex and body and on antennal 
otties 
Viv. 
Alate : 
(27 — 42) (sen 5-19) (29-39) (sen. 2~10) 
Shas spe, tba name 
(,90- a Ss) 
4-6 —.60) (sen. 0-4) 
a eee os 
Pt Viv. 
(Ant. of &= al viv.) 
Fig. 322. Cachet ribis 
I and II; merely blunt on III, IV and V, rather sparse; on hind tibia blunt. Ocular tubercle 
present. Lateral tubercles not evident. Cornicle slightly clavate, smooth. Cauda tapering, 
with 3 pairs of lateral hairs and one dorsal preapical one. 
