SANBORN : KANSAS APHIDID.E. 19 



stronglj' arched and black. Wings are hyaline. Subcostal 

 vein robust, discoidals slender. Third discoidal obsolete at tho 

 base. All the veins are nearly obsolete at their distal margins. 

 Stigma, costal and subcostal uniformly of a brownish black. 

 Stigma, 0.18 mm. broad and 0.75 mm. long. Distal part of 

 stigma sharp in some, in others more rounded. Total wing 

 expansion, 6.61 mm. Legs dark and slightly pilose, also short 

 in proportion to the body. The distal joint of the tarsus is ex- 

 ceptionally long. Honey-tubes and style are absent. Abdomen 

 pale yellow, with no honey-tubes or style ; total length of body, 

 2.35 mm. 



This form is gregarious and apparently subterranean in habit. 

 April 30 the winged form was taken on the roots of the nastur- 

 tium (Nasttirtiam slnuatum) . The forms at that time seemed to 

 be developing wings for migration. Soon after this time the 

 Kaw river valley was inundated and none of these forms have,; 

 been taken since. On account of their pulverulent secretion^ 

 they can withstand a small amount of water, but enough to kilH 

 their host-plant is too much for them. 



Pemphigus fraxinifolii Riley. Plate IV, fig. 28. 



Head dusky. Antennae dusky and bare ; length of segments : 

 I, 0.05 mm. ; II, 0.07 mm. ; III, 0.25 mm. ; IV, 0.12 mm. ; V, 

 0.16 mm.; VI, 0.28 mm., including the unguis; the unguis 

 alone, 0.03 mm. ; total length of the antenna?, 0.93 mm., ex- 

 tending to the abdomen. Sensoria irregularly circular or nearly 

 transverse, but not encircling the segment; seven on the third 

 joint, four or five on the fourth, the proximal one being quad- 

 rate in outline ; six or seven on the fifth, the distal one being 

 very irregular in outline; about four on the sixth, the distal 

 one being at the base of the unguis. Eyes black ; ocular tuber- 

 cles quite prominent ; one frontal ocellus and three dorsal pairs. 

 The extra two dorsal pairs near the median line may not be 

 ocelli, but they resemble them very much in appearance. Beak 

 dusky, 0.45 mm. long, extending a little more than midway be- 

 tween the pro- and mesocoxne. 



Prothorax short, conspicuously marked with two light-colored 

 circular spots. Thorax dusky, marked near the ventral part 

 with two pear-shaped light spots, as shown in the illustration. 

 Wings hyalinCj with slender pale and frail veins. Stigma, 



