18 KANSAS UNIVERSITY SCIENCE BULLETIN. 



joints longer than the basal portion. Fore wings with the 

 stigma large, the cubital simple, obsolete basally, the two dis- 

 coidals united at the base. Hind wings without discoidal vein. 

 Two distinct tarsal joints and two claws on all the legs. Anal 

 plate flattened, drawn forward dorsally and compressing middle 

 of posterior segments, cauda short, transverse, inconspicuous. 

 Cornicles and excretory glands wanting. 



Genus Pemphigus Hartig. 



Antennae not more than half the length of the body, six- 

 jointed ; third joint about equal to the three following taken 

 together; third, fourth and fifth joints commonly annulated. 

 Eyes large in the winged form, but often rudimentary or absent 

 in the apterous form. Beak moderately long in the adult, but 

 much longer in the young. The first two discoidals arise from 

 nearly the same point, the third is simple and obsolete at the 

 base; stigma rather short and broad. The two discoidals in 

 the caudal wing arise from somewhat of an angle in the sub- 

 costal vein. Thorax much developed and distinctly arched. 

 Legs moderately long in the winged form, but short in the 

 apterous form. Honey-tubes absent. Style rudimentary or 

 absent. 



Pemphigus burrowi, n. sp. Plate IV, fig. 30. 



Head black. Antenmr slightly hirsute, and concolorous with 

 the head ; length of segments : I, 0.05 mm. ; II, 0.07 mm. ; III, 

 0.21 mm.; IV, 0.09 mm.; V, 0.11 mm; VI, 0.16 mm., including 

 unguis, which is 0.03 mm. ; total length, about 0.65 nim. 

 Sensoria mostly transverse, but not encircling the segments as 

 do the sensoria of the S. americana ; on the third joint are five 

 or six ; on the fourth one ; on the fifth are five circular ones in 

 a circular patch at the distal end of the segment, each bordered 

 with a fringe of four or five bristles. The sixth has an ir- 

 regular patch of nearly circular sensoria near the distal end 

 which are bordered with bristles. The eyes are black ; ocelli 

 not prominent, but those near the eyes border them dorso- 

 cephalad very closely. On the front is the one most prominent 

 between the bases of the antennye. All are bordered with black. 

 The beak is dark and extends midway between the first and 

 second coxse, being 0.34 mm. long. 



The prothorax is whitish and very short. The thorax is 



