218 IOWA ACADEMY OF SCIENCES. 



groups, three or four at base, followed by a group of nine, and this by two 

 more widely separated, placed at distal end; radial spines, 13; anal spines, 

 5; longitudinal vein of posterior wing distinct. 



General color fuscous; third and fourth joints of antenna? entirely and 

 sometimes base of fifth, legs, except more or less of dorsal surface, yellow- 

 ish: thorax, especially the sutures, tinged with yellow-ferruginous; abdomen 

 varying from fuscous to yellowish or pale fuscous; apex always dark; dorsal 

 aspect of femora generally concolorous with head; anterior wings sub- 

 fuliginous with a broad, indistinctly defined, pale sub-basal band; posterior 

 wings subhyaline. 



Described from eleven specimens taken at Ames, Iowa, on Cjperus, corn 

 and in sweeping grass in August and November. 



GENUS CHIROTHRIPS, HAL. 



This genus is represented by a single species, CJiirotJirijJs 

 antennata, Osb., which is of a brownish-black color with third 

 joint of antennae paler; second joint is quite characteristic, 

 being trapezoidal with acute angle outward. 



ChirotJtrips antennata, Osb. 



Can. Ent. Vol., XV, p. 154. [1883.] 



GENUS THRIPS. 



A. Head of medium size; eyes moderately prominent; antennal joints 3-5 

 elongate. 1 



AA. Head small; eyes very prominent; antennal joints 3-5 not elongate 

 8 



1 . Antennae eight-jointed 2 



Antenna? seven-jointed _ 7 



2. Sixth joint of antenna? annulated 3 



Sixth joint of antenna? not annulated 6 



3. Ocelli widely separated; long bristles at all angles of pro- 

 thorax; spines present at apex of all tibise, numerous and 



heavy on wings, on radial vein 12-14 4 



Ocelli subapproximate; single bristle of medium length at 

 each posterior angle of prothorax, none at anterior angles; 

 spines present at apex of posterior tibia? only, on radial vein 2 

 ...5 



4. Size medium; head, from dorsal view, rectangular! antennae 



approximate (Euthrips) tritici Fitch. 



Size large; head from above pentagonal; antennae subapprox- 

 imate {Euthrips) mairlis n. sp. 



5. Wings more or less distinctly clouded; brown markings oa 



thorax and band at base of abdominal segments 2-7 distinct 



variabilis, n. sp. 



Wings nearly uniformly fuliginous; brown markings distinct 



on thorax; abdomen immaculate var a. 



Wings and body, pale; markings, obsolete ..var. h. 



Wings distinctly trifasciate; broad brown band on head 



