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 antennas 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 genei-ally 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 Cyperus, corn 

 and in sweeping grass in August and November. 



GENUS CHIROTHRIPS, HAL. 



This genus is represented by a single species, Gldrothrips 

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

 joint of antenDEe paler; second joint is quite characteristic, 

 being trapezoidal with acute angle outward. 



Ghirothrips antennata Osb. 



Can. Eat. 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 



L Antennas eight-jointed.. 2 



Antennas seven-jointed 7 



2. Sixth joint of antennas annulated .3 



Sixth joint of antennee not annulated & 



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

 thorax; spines present at apex of all tibias, 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 tibias only, on radial vein 2 

 5 



4. Size medium; head, from dorsal view, rectangular^ antennas 



approximate (Euthrips) tritid Fitch. 



Size large; head from above pentagonal; antennae subapprox- 

 imate [Euthrips) mairlis n. sp. 



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

 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. b. 



Wings distinctly trifasciate; broad brown band on head 



