344 APHIDS OF THE ROCKY MOUNTAIN REGION 
Myzus wakibae (Hottes) 
Dactynotus wakibae Hottes, 1934:6. 
Myzus wakibae, Palmer, 1936b:746. 
Apterous Summer Vivipara. ‘‘Head and thorax light brown with greenish tinge; ab- 
domen with dark brown patch on lighter brownish green background but dark brown again on 
lateral portion and part of venter; light area about base of each cornicle; antenna progres- 
sively darker beyond base of III; cornicle light brown; tibiae yellowish brown with dark 
tips.”” Body length 1.6-1.76; antenna 2.2; hind tibia 1.17; rostrum attaining 2d coxa. Cornicle 
slender, cylindrical, imbricated; cauda broad tapering to point, bearing 2 pairs of lateral 
hairs. Hairs blunt, inconspicuous. 
Alate Vivipara. ‘‘Head and thorax brown; abdomen brown except greenish interseg- 
mental band between segments I and II and greenish about cornicle bases; appendages 
brown.” Body length 1.75-2; hind tibia 1.5; hind tarsal II .12; antenna 2.15; rostrum attain- 
ing between list and 2d coxae. Cornicle cylindrical, with very faint reticulations. Cauda 
parallel-sided, bearing 2 pairs of lateral hairs. 
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Fig. 413. Myzus wakibae 
Collections. On leaves and stems of Pedicularis canadensis. Colorado: Sky- 
way (on Grand Mesa). Alate and apterous viviparae Aug. 6; rare. 
Type. U.S.N.M., No. 50361. 
Chief Distinguishing Characters. Brown body with green area about each 
cornicle base, faint reticulation on cornicle of alate vivipara, length of rostral 
IV+V (.12-.15). 
Genus Phorodon Passerini 
Passerini, 1860:27. 
Characters. Frontal tubercles each with a fingerlike projection which is 
especially prominent in aptera. Antennal I with medially projecting process. 
Other characters as in Myzus. 
Genotype (fixed by Passerini, 1860), Aphis humuli Schrank. 
Key to Species of Phorodon 
1. IV longer than 3 times hind tarsal II. On Mentha (p. 345).......:.:ccscssecscecesceseceseeseeeeeees menthae 
IV not longer than 3 times hind tarsal II. On Humulus (p. 344)..........:::2:c-ccescssseeseeeee humuli 
Genotype Phorodon humuli (Schrank) 
The Hop Aphid 
Aphis humuli Schrank, 1801:110. 
Phorodon humuli, Riley, 1888:70; Gillette, 1908a:40 and 1909c:354 and 1911c:382 and 
1915a:102; Theobald, 1926:273; Gillette and Palmer, 1934:207. 
Apterous Summer Vivipara. Yellow to pale green, darker on median lines and lateral 
areas; dorsum somewhat rugose; antenna, cauda, rostrum, cornicle and tibiae pale except 
tips of antenna and of tibiae dusky. Frontal tubercles each with a fingerlike process. Body 
length 1-2.3; across eyes .26-.30; hind tibia .42-.78; hind tarsal II .06-.08; antenna .93-1.09; 
rostrum attaining between 2d and 3d coxae. Hairs on body not noticeable. Cornicle cylin- 
drical slightly recurved, imbricated. Cauda rather broad and tapering, bearing 3-4 hairs on 
each side. 
Alate Vivipara. Head and thorax dark; abdomen pale yellowish green with dorsal bands, 
nearly coalescing on III, IV and V, and lateral areas dark; antenna except base of III, 
cornicle and tibiae dusky; cauda pale to dusky. Body length 1.5-1.8; across eyes .30-.35; hind 
tibia 1-1.3; antenna 1.66-1.85. Hairs on body not evident. Cornicle and cauda as in apterous 
vivipara, 
