CRAWFORD. SOME THYSANOPTERA OF MEXICO AND THE SOUTH 117 



broad, and about as long as prothorax ; cheeks parallel ; anterior angles con- 

 cave to receive antennae ; a concavity between insertion of antennae : four in- 

 conspicuous spines on anterior half of dorsal surface, one pair in front and 

 the other pair behind the eyes, and one small spine on each cheek. Eyes ex- 

 tremely small, dark, with two or three widely separated facets, which are 

 light, the rest of the eye apparently blind ; no ocelli present. Mouth cone long, 

 broad, and broadly rounded at tip, reaching almost to posterior margin of 

 prothorax ; maxillary and labial palpi one-segmented, the latter short. Anten- 

 nae (Fig. 52 D) seven-segmented, long and slender, more than two and one- 

 half times as long as head; two basal segments rectangular in shape, I shorter 

 than II ; III very elongate, enlarged at both ends, sides rough ; IV to VI elon- 

 gate, but shorter than III, with a sense cone on distal end of each ; VII bluntly 

 pointed at tip, with an obscure suture just beyong the middle and another more 

 obscure midway between the first suture and the tip; segments II, III, and 

 VII with three or four long slender spines at apical end ; IV to VI with one 

 spine on side opposite to the sense cone; III light brown, except distal one- 

 sixth, the rest of the segments concolorous with body. 



Prothorax (Fig. 52 A) about one and two-thirds times as wide as long, 

 narrowed anteriorly and bulging midlaterally, partly due to fore-coxae ; two 

 rectangular chitinous plates between fore-coxae, each bearing two spines ; no 

 other spines on prothorax. Mesothorax (Fig. 52 A) about as long as pro- 

 thorax, and one and one-half times as wide posteriorly ; sides diverging to 

 midpoint, and from there to posterior margin of metathorax, sides about 

 parallel, slightly diverging; with a pair of large facetted spiracular plates 

 (Fig. 52 H) near anterior angles, with closely crowded facets; dorsal surface 

 of both meso- and metathorax and all but two anal abdominal segments, with 

 irregular chitinous plates (Fig 52 A), most of which bear one spine, a few 

 with two spines, and some with none ; these are scattered promiscuously over 

 the dorsal surface, and are distinctly convex ; spines moderately long and 

 stout ; the rest of the body surface, both dorsal and ventral, apparently very 

 weakly chitinized. Metathorax shorter and slightly wider than mesothorax, 

 diverging somewhat to midpoint of pleurae, and then converging, but slightly 

 wider posteriorly than anteriorly ; hind coxae almost as widely separated as 

 middle pair. All thoracic spines set on chitinous plates. Legs (Fig. 52, E, 

 F, C) moderately long, with roughened surface; with several extremely long 

 and slender spines on all femora and tibiae, and several other shorter ones 

 on each; distal end of tibiae, without, with a very long, remarkable, spear- 

 shaped spine (Fig. 52 G) ; tarsi almost abortive; middle tarsi with a heavy 

 setigerous projection on each side of the bladder. Wings not present. 



xAbdomen (Fig. 52 B) long, unifonnly tapering from posterior margin 

 of metathorax to tip ; segments one to six, with numerous irregular chitinous 

 plates ; as described above, and segments seven and eight with two or three 

 larger and more symmetrical plates, with several spines; two anal segments 

 long and tube-like, and heavily chitinized over entire surface. dee]i black ; 

 ninth seynienl with oiHit hnvj; slender liristles on distal end; airil segment 



