IOWA ACADEMY OP SCIENCES. 221 



across whole anterior border; ocellar area small, elevated; ocelli approxi- 

 mate, inner margins heavy, conspicuous: ocellar bristles not more than 

 one-half the length of the head; eyes large, prominent, feebly pilose. 

 Antennge eight-jointed, distant, moderately bristly; basal joint short, 

 thick, hidden from dorsal view by vertex; the following joint longer, more 

 robust, globose; joints 3-6 elongate; joint 3 the longest, subfusiform; joint 

 4 a little shorter than joint 3, elongate-modioliform; joint 5 obovate, inter- 

 mediate in length between 2 and 4; the remaining joints sessile, together 

 eloE gate-conic?.,]; joint 6 equal to joint 4 but a little stouter; joints 7 and 8 

 minute, together one-half as long as preceding, line of separation between 

 them oblique; sensorial spines on joint 6 originate beyond middle; four 

 short bristles in transverse row on front above antennas, and one behind 

 each eye; mouth parts nearly symmetrical. 



Prothorax broader than long; anterior angles prominent, rectangular; 

 posterior angles broadly rounded and furnished with a single bristle; sur- 

 face plainly and uniformly marked with transverse strice, with a few short 

 slender bristles on front margin and more on disc Mesoscutum is quite con- 

 vex from base to apex, marked with fine transverse strias, and provided 

 with four short bristles on disc. Scutellum with triangular area at base 

 striate as in mesoscutum, furnished with four basal bristles. 



Abdomen broad, ovate; sides, under high power, appear thickly set 

 with minute appressed hairs; a pair of bristles occurs on disc of each seg- 

 ment from the second to the seventh; they are approximate on the second 

 and gradually become more widely separated on the succeeding segments; 

 lateral bristles few and short; apical border at sides and on ventral surface of 

 segments bordered with minute ciliie interspersed with coarse hairs or 

 bristles: caudal spines rather light; those on penultimate segment directed 

 backward and extending only to base of following segment; terminal spines 

 a little longer than the preceding, radiating at tides. 



Legs very slender, somewhat bristly; tarsi elongate; anterior femora 

 not dilated; apex of intermediate and posterior tibias and of posterior tarsal 

 joints terminating in short spines; inner margin of posterior tibiae feebly 

 spinose. 



Wings; veins heavy; in anterior pair radius and cross veins obsolete; 

 costal spines number 22-30; cubital, 20-2K, arranged in two series; radial, 2; 

 anal, 4; one near base of anal cell; longitudinal vein of posterior wing very 

 heavy for two-thirds of the length. 



Male. Length, 78-86 mm. Resembles the female very closely. 

 Dilfers in being of smaller size, in having from 23-25 costal spines, 20-21 

 cubital: the remaining spines on the wing as in female. The apex of the 

 abdomen is more blunt; the anal segment is cleft on either side, the lateral 

 lobes terminate in two spines; the middle lobe is prolonged consider- 

 ably beyond the lateral lobes, making apex more pointed than apex of 

 male of T. tritici. The spines on preanal segment are similar to those 

 in female. 



This species presents coasiderable variation in color. The extreme 

 forms are quite distinct and might almost be considered separate species 

 were it not that in addition to the similarity in structure there is the occur- 

 rence of a series of intergradient forms. 



