NO. 1310. NORTH AMERICAN THYSANOPTERA— HINDS. 143 



(appearing as a stripe) extends across two-thirds of the width of the 

 dorsal plates of segments two to seven near their anterior edges; 

 spines upon terminal segments short and weak. 



This species possesses a Avell-developed power of leaping. 



Described from twenty specimens. 



( 'otype.—C?^. No. 6327, LI.S.N.M. 



}[((]('. — Length 0.87 mm. (0.66 to 1 mm.); width of mesothorax 

 0.21 mm.; width of abdomen, 0.27 mm. (0.22 to 0.30 mm.). 



Relative lengths of antennal segments: 



_1_ J_ 3 ^ _5_ _6_ J_ ^ 

 5.8 9.3 15 12.8 10.3 12.8 2.8 3.7 



End of abdomen shaped as in female; a transverse elliptical depres- 

 sion in the middle of ventral plates of segments five to seven. Seg- 

 ment nine long and tapering; tenth elongate and retracted within the 

 ninth. Genital apparatus appears to be wholly protrusile. Testes 

 large and brownish yellow in color. 



Cotype.—C^t. No. 6327, U.S.N.M. 



Food j^l'^int-s. — Various grasses. 



Ildhltat. — Amherst, Massachusetts. 



Life history unknown. 



SERICOTHRIPS VARIABILIS (Beach). 



Plate II, li^. 23; Plate III, figs. 24-26. 

 Thrips variabilis Beach, Proc. Iowa Acad. Sci., 1895, III, 1896, pp. 220-223. 



Feviale. — Length 0.84 to 1.23 mm.; width of mesothorax about one- 

 fourth the length of the body. General color yellow, with more or 

 less striking brown or graj^-brown markings. 



Head about two-thirds as long as broad, broadest through eyes, 

 retracted considerably into prothorax; cheeks moderately full, con- 

 verging somewhat posteriorly; anterior margin nearly straight, but 

 slightly elevated between bases of antennae. Spines upon head incon- 

 spicuous; but one moderately long spine on each side of fore ocellus, 

 and one behind each hind ocellus; a row of four short, strongly curved 

 spines across front near margin, and a few small spines upon cheeks; 

 color of head pale yellow with dusky shadings. Eyes moderately large, 

 protruding a little, nearly black, coarsely faceted, plainly pilose, occu- 

 P3'ing about three-fifths the width of the head; ocelli large, approxi- 

 mate, reddish orange, heavily margined inwardly with maroon, situated 

 upon a slight]}" raised area between the eyes. Mouth cone tipped with 

 black; maxillary palpi slender, three segmented. Antenna^ eight seg- 

 mented, more than twice as long as head, bases separated by about 

 two-thirds the width of a basal segment; relative lengths of segments: 



