14 NORTH AMEEICAN THYSANOPTEEA. 



a. Without white band around first two abdominal segments; last four segments of 

 antennae approximately as long as the fifth alone. 



(7) Molothrips fasciatus Linnaeus. 

 2. Each fore wing with dark longitudinal band along posterior margin. 



a. With veins in anterior wings normal as in most species of this genus. 



(8) Molothrips kuwanaii Moulton. 

 a'. Without veins in anterior wings (9) Molothrips longiceps Crawford. 



(7) Genus Thrips Linnaeus. 



1. Head considerably wider than long. 



a. Body color dark brown, thorax and other parts orange-tinted, inner crescents 

 bordering ocelli orange-red; individuals large, about 1.25 mm. in 

 length. 

 b. Wings light brown, with lighter colored area near base. 



(12) Thrips madronii Moulton. 



h' . Wings uniform dark brown to brown (13) Thrips magnus, new species. 



a'. Body color light yellow to light brown or brown; inner crescents bordering ocelli 

 light brown; body length about 1 mm. 

 b. Ocelli subapproximate; posterior longitudinal vein of fore wing with about 

 foiu-teen to seventeen regularly placed spines. 



(14) Thrips tabaci Lindeman. 

 b\ Ocelli widely separated, anterior one on frons and directed forward ; posterior 

 longitudinal vein bearing about seven spines. 



(15) Thri.ps abdominalis Crawford. 



2. Head about as long as wide. 



a. Color uniform light lemon-yellow (16) Thrips bremnerii Moulton. 



a'. Color of head brown, of thorax reddish orange-brown, of abdomen pale yellow to 

 gray-brown (17) Thrips perplexus Beach. 



(8) Genus Heliothrips Haliday. 



1. All tibise yellow. 



a. Antennae nearly three times as long as head; wings shaded brown, with two more 

 or less distinct whitish cross-bands and whitish at tip. 



(18) Heliothrips femoralis Renter. 



a^. Antennae about twice as long as head; wings almost white, shaded light brown 

 along veins (19) Heliothrips hasmorrhoidalis Bouch6. 



2. Middle and hind tibiae brown. 



a. Antennae two and one-half times as long as head, segments 3 and 4 modioliform, 

 maxillary palpi three-segmented . . . (20) Heliothrips fasdatus Pergande. 



a\ Antennae twice as long as head, segments 3 and 4 fusiform; maxillary palpi two- 

 segmented (21) Heliothrips fasdapennis Hinds. 



(11) Genus Sericothrips Haliday. 



1. Wings fully developed or rudimentary. 

 a. Wings fully developed. 



6. Fore wings dusky or gray-brown and more or less distinctly marked with whitish 

 cross-bands; general color yellowish to dusky gray. 



(24) Sericothrips variabilis Beach. 

 y. Fore wings black, with two broad white cross-bands, and white at tip; general 



color blackish (25) Sericothrips pulchellus Hood. 



a'. Wings reduced or fully developed; body dark brown to nearly black, except seg- 

 ments 4, 5, and 6 of abdomen, which are almost white. 



(26) Sericothrips cingulatus Hinds. 



