218 APHIDS OF THE ROCKY MOUNTAIN REGION 
Hairs pointed; .02-.03 long, drooping and sparse on body. Lateral tubercles present but small. 
Fore wing with 2d fork of media unusually short, arising at hardly third the distance from 
margin of wing to 1st fork. 
Collections. On leaves and stems of corn (Zea mays), Sorghum vulgare and 
the following grasses: Oat (Avena sativa), Echinochloa crusgalli, barley (Hor- 
deum vulgare), Panicum capillare, Setaria viridis, and wheat (Triticum vul- 
gare). Throughout region. Apterous and alate viviparae March 21 to Nov. 19; 
fairly common. 
Cotypes. U.S.N.M. 
Chief Distinguishing Characters. Color of body (bluish green without red- 
dish coloration about cornicle bases), shape of cauda (approximately spoon- 
shaped) and number of lateral hairs on cauda (2 pairs), broad, short rostral 
IV+-V (.09 by .05), number of sensoria on III of alate vivipara (14-18), length of 
unguis (.15-.26), and length of cornicle (.20-.30). 
Genotype Rhopalosiphum nymphaeae (Linneaus) 
The Waterlily Aphid | 
Aphis nymphaeae Linnaeus, 1761:260; Kaltenbach, 1843:104. 
Aphis aquatica Jackson, 1908a:243; Davis, 1910a:245 (synonymy discussed). 
Rhopalosiphum nymphaeae, Patch, 1912a:171 and 1915b:164; Davidson (W.M.), 1917a: 
350; Theobald, 1927:60; Gillette and Palmer, 1932b:479. 
Apterous Summer Vivipara. Light olive-green to golden brown; pulverulent on sides of 
head and prothorax; all appendages dusky except cornicle lighter proximally. Body length 
2-2.30; hind tibia .95-1.10; antenna 1.20-1.50; rostrum obtuse, attaining 3d coxa. 
Alate Vivipara. Color and measurements same as apterous vivipara except as figured. 
Cornicle clavate, swollen on distal half and with distinct flange, narrow portion with faint 
transverse wrinkles, otherwise smooth. Hairs pointed; .01-.02 on body. Cauda blunt, parallel- 
sided with slight neck, bearing 2 hairs on each side. Lateral tubercles small but present on 
prothorax and abdominal segments. Fore wing with 2d fork of media short, arising about 
quarter the distance from margin of wing to 1st fork. 
Ovipara.* Apterous. With hind tibia considerably swollen and bearing numerous sen- 
soria. 
Male.* Alate. 
Fig. 255. Rhopalosiphum nymphaeae 
Collections. As winter host, on leaves and stems of plum (Prunus sp.) ; sum- 
mer hosts, on leaves and stems of Berula erecta, Bidens sp., Ceratophyllum sp., 
Cicuta douglasi, Leersia oryzoides, Mimulus floribundus (?), yellow pond lily 
(Nuphar polysepala), Polygonum sp., P. punctatum, Ranunculus sp., Sagit- 
taria sp., Scirpus sp., Typha latifolia and Veronica sp. Colorado: Fort Collins, 
Longmont and Fruita. Utah: Blacksmith Fork Canyon, Garfield, Logan, Loco- | 
motive Springs and American Fork. Apterous and alate summer viviparae June 
14 to Dec. 3; common. 
Chief Distinguishing Characters. Green to olive-brown body, long rostral 
IV |-V (.15), shape of cornicle and approximately spoon-shaped cauda. 
*According to Theobald (op. cit.). 
