Pomona College Journal op Entomology 793 



— SiUiiU, nearly as louy- as wide, with disliuct, but short, aiiluuual tuburdus, 

 pointed in front, ihuk with amber or brown front. Eyes — Dark red, to brown. 

 AiilciiiMv— (F'tgwm 251, 7). Louyer Uian half the leiij^th of the body, reaching 

 to the bases of the cornicles, with very few hairs, imbricated; articles 1 and 

 11 dark amber brown, III dark amber base and remainder amber, IV, V, VI 

 dark brown to nearly black. Lengths of the articles: I, O.U'J mm.; 11, U.UtJ 

 mm.; Ill, 0.3 mm.; IV, 0.2 nnu.; V, 0.17 mm.; VI, 0.56 mm., (spur or filament, 

 0.47 mm.) ; total 1.38 mm. From these measurements it will be seen that the 

 articles bear a similar relation to each other as do the articles of the antennse 

 of the winged female and that the filament is longer than article III. (There 

 seem to be no individuals in which this is reversed) . Sensoria only on articles 

 V and VI and on these normal, liostrum — Reaching to back margin of the 

 second coxaj, amber with dark base and tip. L'rolhorax — Slightly wider than 

 the head, with distinct lateral tubercles. All thorax black and distinctly 

 segmented with mesothorax very short. Abdomen — Smooth, dull black or 

 very dark green, with one lateral anterior and a lateral posterior tubercle on 

 each side, segmentation on the dorsum partial or indistinct. Anal plate black 

 or very dark. Co/vacies— (Figure 251, 6). Cylindrical, smooth— not imbri- 

 cated as in the winged forms — not reaching to the tip of the abdomen, some- 

 times slightly flaring in the middle, constricted just before the mouth which is 

 flared, black, length 0.31 mm., average width 0.051 mm. Legs — Lighter than 

 in winged form; coxie amber-yellow; femora with tip and front darker; tibiie 

 same as femora; tarsi dark brown. Htylc — Slender, nearly cylindrical, half 

 as long as the cornicles, dark green to nearly black, hairy. 



Hosts — Occurs in more or less limited numbers on the ears and tassels of 

 the common sweet corn. In the corn-growing States of the Mississippi Valley 

 this insect is a most serious pest and much study has been given to perfect 

 control methods. It attacks practically all members of the sorghum or corn 

 family, and has been reported from practically every State in the United 

 States and from the Hawaiian Islands. Prof. Clarke reported it from this 

 State in the year 1903, but since that time it has received little or no attention. 



Locality — Collected by the author in the vicinity of Santa Paula, lie- 

 ported from the central part of the State by Prof. Clarke and W. JM. Davidson. 



Date of collection — Occurs throughout the sumiiiei- months. Specimens 

 studied were collected July 28, 1911. Serial number 48. 



Natural Enemies — This species is quite extensively parasitized by internal 

 parasites. The larv:e of the native Scymnus (S. sordidus Horn) and the 

 larvas of Syrphid Flies play an important part in keeping it down. 



Rhopalosiphum nymphaeae Linn. 

 (Pond Lily Aphid) 



1767 Aphis nympliaeae Linn. Syst. Nat. II, p. 734. 



1794 Aphis nymphaeae Linn. Fabr. Ent. Syst. IV, p. 214. 



1801 Aphis )iyinp]iacae hmn. Schrank. Pn. Boica. II, p. 117. 



1801 Aphis butomi Hchremk. Fn. Boica., p. 114. 



