The Aphididae of Nebraska 33 



Winged form: "Dorsum without conspicuous tubercles. Ill twice as 

 long as IV; IV and V subequal ; VI and VII subequal. Wings with mar- 

 ginal cell hyaline. Veins bordered with brown. Basal half of stigmal 

 vein subobsolete and not thickened and dusky at the base. Length of 

 body 1.60-2 mm., to tip of wings about 3.30 mm., antennae 2.40 mm." 

 (Monell). 



Ashland, apterous form quite common on leaves of red clover 

 (Trifolium pratense) during the month of September, 1890. 



Specimens in collection of the University of Nebraska (nos. 41, 

 42) and of the U. S. National Museum (no. 22). 



2,6. Callipterus ulmifolii Monell. 



Monell, Bull. U. S. Geol. Sur. Ter., Vol. V, No. 1, p. 29 (1879) 

 Thomas, Ins. 111., 8th Rep., p. in (1879). C. ulmicola. 

 Oestlund, Syn. Aph. Minn., p. 42 (1887). C. ulmifolii. 

 " Pale whitish yellow. Apterous individuals : Tuberculate, with capitate 

 hairs, which disappear when the insect acquires wings." 



" Winged individuals : Antennae as long as the body ; III, IV and some- 

 times V slightly dusky at apex; apical joint a very little longer or shorter 

 than the sixth. W r ings hyaline; all the veins and especially the stigmal 

 vein subhyaline. Dorsum with four long, spine-like tubercles on its basal 

 portion and with various shorter tubercles on the apical portion." 

 " Length 1.77 mm., to tip of wings 3.04 mm." 



On under side of leaves of elm (Ulmus americana) , evidently 

 causing them to cup slightly. Lincoln, October 4, 1888, and June 

 13, 1890. Ashland, June to July, 1890. 



Specimens in collection of the University of Nebraska (nos. 43, 

 44) and of the U. S. National Museum (no. 23). 



37. Drepanosiphum acerifolii (Thomas). 



Thomas, Bull. 111. Lab. Nat. Hist, 2, p. 4 (1878). Siphonophora 



acerifolii. 

 Thomas, Ins. 111., 8th Rep., p. 47 (1879). Siphonophora acerifolii. 

 Monell, Bull. U. S. Geol. Sur. Ter., V, I, p. 27 (1879). Drepano- 

 siphum acerifolii. 

 Oestlund, Syn. Aph. Minn., p. 46 (1887). Drepanosiphum acerifolii. 

 Apterous form: Pale green. Antennae very long, pale, with articulations 

 and the very long thread-like VII dusky. Eyes red. Legs pale, with 

 dusky joints and tarsi. Honey tubes very large at base, tapering, with a 

 rimmed apex, pale. Tail none. 



Winged form: Color gray varied with white and brown. Head and 

 thorax brown, with various whiter markings. Antennae much longer than 



117 



