292 FAMILY VI. ACUIKID.E. THE LOCUSTS. 



Caudell (1004f) having shown that both Tr'unerotropis c in eta 

 Thos. and .]/. chirfa Thos. were based on the single description of 

 OcdijHx-ld chtctd Thos. (1X70, 80), the name cinrtd rightfully be- 

 longing to the former. 



III. TRIMEKOTIIOIMS StAl, 1873, 118. ( Gr.. "three" -f "part" 



-f "keel.") 



Medium or rather large sized species, having the head slightly 

 exceeding the prozona in width, but always narrower than meta- 

 zona, which is considerably expanded; vertex with disk longer 

 than broad, its sides distinct, often sinuous, gradually converging, 

 and continuous with those of frontal costa ; median carina, if 

 present, faint; foveolae small, distinct, triangular; frontal costa 

 slightly narrower just below ocellus and at point of union with 

 vertex, in our species with at least the lower two-thirds strongly 

 sulcate; antennae filiform, longer than head and prouotum, male; 

 pronotnm with disk nearly flat, either smooth or with minute 

 tubercles on metazona ; hind margin either acute- right- or obtuse- 

 angled ; median carina low, especially on metazona, cut by two 

 notches, the hindmost of which is much in advance of the middle 

 (Fig. 100, c) ; lateral carime rounded, indistinct; lateral lobes of 

 pronotum with front and hind margins nearly vertical, lower 

 margin with its front half oblique, ascending, the posterior half 

 arcuate, the angle well rounded; tegmina much exceeding the ab- 

 domen in both sexes; hind femora of average width, reaching or 

 exceeding the tip of abdomen in both sexes; valves of ovipositor 

 slender, strongly exserted, their tips curved, pointed. 



McNeil!, in his monograph of this genus (1001), described and 

 gave keys to 54 nominal species. Of these 40 were from the 

 United States. 1(5 of which are confined to California, while but 

 three occur east of the Mississippi River. One species and a va- 

 riety have been since described from our territory. Kirby (1010, 

 LTi.'l, L'55 ) divides the genus into two, Trinicrotrojii.^ and I'xcitiln- 

 trimerotropis, the latter a suhgeneric name proposed by Kehn 

 (1001. :::!4) to replace McXeill's subgenus TriiiHTotro/ii* (1001. 

 .'500), which was wrongly used. To Trintcrotropix. with iiidritinid 

 as the type, Kirby accredits 17 species, and to Pseudotrimerotropis 

 with chn-td Thos. as the type, 54 species, (""audell has shown 

 ( 1011. 1(54) that Helm's name is, as he proposed it, of subgeneric 

 rank only. 



KEY TO EASTERN SPECIES OF TRIMEUOTROI'IS. 



o. Tegmina plain grayish-buff or brownish-yellow, not or faintly barred 

 with fuscous: disk of prozona behind the first notch flat or nearly 

 so; inner face of knees of hind femora pale. 



