794 Pomona College Journal of Entomology 



1843 Aphis nymphttcac Linn. Kalt. Jlon. Pflz., p. 104. 



1854 Bhopalo.siph iini iiynipliacae hinn. Koch. Pflz., pp. 44-45. 



1854 Rhopalosiphum alismae Koch. Pflz., pp. 26, 44. 



1854 Rhopalosiphum najaduni Koch. Pflz., pp. 45-4() 



1879 Rhopalosiphum nymphaeae Linn. Buck. Mon. lirt Ajjhid., II, p. 12. 



1893 Rhopalosiphum nymphaeae Linn. Osborne-Sirrine. Proc. la. 



Acad. Sci., Ill, p. 98. 

 1893 Rhopalosiphum nymphaeae Linn. Osl)orne-Sirrine. Insect Life, V, 



p. 236. 

 1895 Rhopalosiphum nymphaeae Linn. Cowen. Ileiii. Colo., p. 123. 

 1901 Rhopalosiphum nymphaeae Linn. Hunter. Aphid. N. A., pp. 106- 



107. 

 1905 Rhopalosiphutn nympliaeaeFa.hr. Schout. Apliid. Belg., p. 236. 

 1905 Rhopalosiphum nymphaeae (Linn.) Kirkaldy. Can. Ent. 



XXXVII, p. 415. 

 1908 Aphis aquaticus Jackson. Ohio Natr., VIII, p. 243. 

 1910 Rhopalosiphum nymphaeae (Linn.) Williams. Aphid. Nebr., p. 70. 

 1910 Rhopalosiphum nymphaeae (Linn.) Davis. Ent. News, XXI, pp. 



245-247. 

 1910 Rhopalosiphum numphaeae Linn. Davidson. Jr. Ec. Ent. Ill, p. 



377. 

 1910 Rhopalosiphum nymphaeae Linn. Davis. Jr. Ee. Ent., Ill, p. 494. 



WTNGED vivir.vRous FEMALE (Figure 252, A) 



Length of body 1.5 mm., width of the mesothorax 0.4 mm., width of the 

 abdomen, 0.65 mm., wing expansion 4.8 mm. Body — Small, oval to oblong 

 in shape, dark, dorsum smooth and often shiny, ventral surfaces of the thorax, 

 head, antennae and legs covered with rather long white flocculence. This is 

 secreted on the lower surface of the thorax and is evidently gathered up by 

 the appendages coming in contact with it. Prevailing color — Light yellowish- 

 green to a dark olive to almost blackish-green, with the white flocculence under 

 the thorax. Head — Nearly as w-ide as the prothorax, pointed In front, with 

 small frontal tubercles, dark olive-green, pruinose ventrally. Eyes — With 

 distinct tubercles, large, red. ^l«<e«»ae— (Figure 252, 1, 2). Reaching to the 

 middle of the abdomen, but not to the bases of the cornicles, on short but 

 distinct frontal tubercles, which are wide apart at the ba.se, imbricated, with 

 very few hairs, dull olive green to dark amber throughout. I^engtiis of articles: 

 I, 0.05 mm.; II, 0.05 mm.; Ill, 0.25 mm.; IV, 0.14 mm.; V, 0.118 mm.; VI, 

 0.38 mm., (base 0.09 mm., spur 0.29 mm.) ; total 0.988 mm. Articles I and 

 II large and co-equal; III longer than either IV or V, but not quite as long as 

 the two together, IV always slightly longer than V, VI longer than any of 

 the rest, the base much shorter than either IV or V, the spur longer than III 

 and longer tiian IV and V together, the apical fourth is not imbricated at all, 

 a very notic('al)le characteristic. The sensoria are circular and vary in size 

 and .siiape as well as in iimiihcr. Artidr 111 has from five to thirteen, but 



