SUBFAMILY APHINAE 153 
Ovipara. Apterous. Body length 1.6; hind tibia .63; hind tarsal II .12; otherwise as in 
apterous vivipara except hind tibia which is slightly swollen on proximal third and bearing 
a few scattered faint sensoria. 
Male. Apterous. Body length 1.2-1.3; hind tibia .60; antenna .70; cornicle .08. 
Collections. On roots of Aster sp., Artemisia aromatica, Mentha canadensis 
and dandelion (Taraxacum officinale). Colorado: Hotchkiss and Fort Collins. 
Apterous summer viviparae July 14 to Nov. 5, alate viviparae July 14, sexuales 
Nov. 5; not common. 
Cotypes. U.S.N.M. 
Chief Distinguishing Characters. Length of antenna (1.03, II .23-.30), 
length of hind tarsal II (.14) and character of hind tibia of ovipara. 
This species is very clese to A. middletonii Thomas and A. maidi-radicis. It 
was stated to be a synonym of the latter species by Vickery (1910:112) acting 
on the tentative opinion of Gillette (expressed in correspondence) on comparing 
viviparae. Gillette (Vickery, op. cit.) stated that there were slight differences 
but doubted their being sufficient to separate the species. Later a study of 
sexuales shows the hind tibia of the ovipara of menthae-radicis to be less 
swollen and bearing a much smaller number of sensoria than in maidi-radicis. 
Aphis minutissima Gillette and Palmer 
Anuraphis minutissima Gillette and Palmer, 1928:8. 
Aphis minutissima, Gillette and Palmer, 1932b:420. 
Apterous Summer Vivipara. Dark brown to black; covered throughout with powdery 
reticulations; appendages black except base of antennal III and middle of tibiae which are 
dusky. Body length .95-1.25; hind tibia .30-.40; hind tarsal II .09; antenna .40-.50; rostrum 
attaining abdominal I. Hairs as in alate vivipara except on vertex .04-.05. 
inion Myra 
06-08 08 017 04-08 2 
-Fig. 171. Aphis minutissima 
Alate Vivipara. Black throughout; abdomen covered with white powdery reticulation; 
otherwise as in apterous vivipara. Body length 1.30; hind tibia .50; antenna .54-.60; cornicle, 
cauda and hind tarsal II as in apterous vivipara. Hairs pointed; sparse and .01 long on III; 
on vertex .03; on hind tibia .03, rather numerous. Cauda broadly tapering, bearing two pairs 
of lateral and one pair of dorsal preapical hairs. 
Ovipara. Apterous. Color same as apterous vivipara. Body length 1.35, other measure- 
ments as in vivipara. Hind tibia conspicuously swollen and bearing numerous large sensoria. 
Male. Alate. Color same as alate vivipara. Body length .90 to 1; hind tibia .40; antenna 
.60, with numerous sensoria on III, IV and V. 
Collections. On leaves and stems of Artemisia filifolia and A. tridentata. 
Colorado: Denver. Utah: Trenton, Brigham and Castleford. Idaho: Twin Falls 
and Rexburg. Apterous summer viviparae April 30 to Oct. 8, alate viviparae 
July 10 and Aug. 14, sexuales Oct. 8; rather rare but abundant at times. 
Type. U.S.N.M., No. 41973. Paratypes, Colo. Agr. Exp. Sta. Collection. 
Chief Distinguishing Characters. Very short cornicle and cauda, small 
number of hairs on the cauda, short unguis (shorter than base of VI), uniform 
covering of white reticulation on dorsum and much swollen hind tibia of 
ovipara, covered with rather large sensoria. 
