jo Thomas Albert Williams 



Specimens in the collection of the University of Nebraska (nos. 

 113, 116) and of the U. S. National Museum (nos. 25, 29). 



87. Rhopalosiphum dianthi var. poae n. var. 



This differs from the preceding in the pupa having dusky wing- 

 pads and legs, and the winged form having III and IV of the 

 antennae covered with many roundish sensoria, the abdomen with 

 few darker markings, legs darker and tail very short (0.10 to 0.15 

 mm.) and acutely conical. The insect is somewhat smaller. 



This may be distinct enough to deserve specific rank, but I have 

 never seen winged specimens of R. dianthi, so am loath to put it 

 as such till I have a better understanding of that species at least. 

 This form is at least deserving of varietal rank. 



On lower leaves and stems of bluegrass {Poa sp. ?), in the 

 greenhouse at the University of Nebraska, February 1, 1890. 



Cotypes in the collection of the University of Nebraska (no. 

 119) and of the U. S. National Museum (no. 26). 



88. Rhopalosiphum nymphaeae (Linnaeus). 



Linnaeus, Syst. Nat., I, 2, p. 734 (1767). Aphis nymphaeae. 

 Fabricius, Ent. Syst., IV, p. 214 (1794). Aphis nymphaeae. 

 Schrank, Fn. Boi., II, p. 117 (1801). Aphis nymphaeae. 

 Kaltenbach, Mon. Pflan., p. 104 (1843). Aphis nymphaeae. 

 Koch, Die Pflan., pp. 26, 44, figs. 33, 34, 35, 57. Rhopalosiphum 



nymphaeae. 

 Koch, /. c.j p. 45, fig. 58 (1854). R. najadam. 



Buckton, Mon. Brit. Aph., II, p. 12, pi. XLI, figs. 1-3 (1879). R. 

 nymphaeae. 

 Apterous viviparous female: Broadly oval; dark olive green variously 

 mottled with lighter green. Some specimens are quite glaucous, while 

 others are smooth and shining. Antennae, legs, honey tubes, anal plates 

 and tail black. Antennae about half the body in length. Beak reaching 

 to hind coxae. Eyes dark reddish brown. Honey tubes clavate. Tail 

 short and acute. 



Pupa: Smaller; wing-pads blackish; honey tubes shorter; tail short and 

 conical; otherwise as in the female. 



Winged viviparous female: Head, thorax and antennae black, the latter 

 on moderately sized tubercles, minutely annulate. Prothorax brown. Ab- 

 domen olive green, with three or four black marginal spots and various 

 darker markings along the dorsum. In some specimens the darker mark- 

 ings are almost entirely wanting, while in others they are very prominent. 



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