220 FAMILY VI. ACRIDIDJE. THE LOCUSTS. 



bly flattened, shorter, female, or equalling, male, the length of 

 head and prouotum; disk of pronoturn somewhat tectiforni, its 

 hind margin slightl}' rounded, median carina distinct, cut at or 

 slightly behind middle by the principal sulcus ; lateral lobes slight- 

 ly higher than long, front margin oblique, hind one nearly ver- 

 tical, lower one with front half ascending; tegmina and hind 

 femora exceeding the abdomen in both sexes ; hind tibire with 12 

 13 spines on outer margin ; subgenital plate of male short, as- 

 cending, obtuse; ovipositor with upper valves included, lower ones 

 feebly exserted. 



The range of one of the two known western species overlaps 

 our territory. 



93. AMPHITORNUS BICOLOB (Thomas), 1872, 465. Bicolored Locust. 



Rather slender, the male but little the smaller. Brownish-yellow; 

 dorsal surface with a broad yellow stripe beginning at vertex and usually 

 extending back nearly or fully to tips of tegmina, this bordered below 

 each side with a brown stripe of almost equal width and length; sides of 

 head and pronotum also with a narrower yellow postocular stripe extend- 

 ing backward along the costal margin of tegmina; a broad, oblique yel- 

 lowish stripe starting near base of antennae extends down each cheek and 

 back across the lower edge of pronotal lateral lobe, and a narrow yellow 

 stripe extends from below each eye back along the middle of each lateral 

 lobe; hind femora with three oblique fuscous bars on outer face, knees 

 black; hind tibiae blue, their spines tipped with black. Structural char- 

 acters as given above. Length of body, $, 17 19, 9,20 22; of antennae, 

 (5,9, $, 8; of tegmina, $ and 9, 15 17; of hind femora, $ and 9, 

 12 13 mm. 



This handsome Tryxalid is a species of western range or, as 

 Bnmer has put it, a "characteristic species of the Great Plains." 

 It is included here on account of its occurrence in Illinois, it hav- 

 ing been recorded by Hart (1907, 231) as occurring at the "Devil's 

 Neck," a large area of barren sands and blowouts ten miles north 

 of Havana. There it was found only on grassy dune summits near 

 the middle of an old post-glacial lake. Hart (1917, Ms.) says: 

 "We have numerous specimens, all from the one vicinity north of 

 Havana. I have not found it established elsewhere, but expect it 

 may occur in the sand regions between Galena and Savanna along 

 the Mississippi in northwestern Illinois which I have not yet 

 visited." 



Specimens at hand are from Colorado, Valentine, Nebraska 

 and Morton and Ford counties, Kansas. Thomas gave the locality 

 of his types as "Colorado and Wyoming east of the mountains, 

 where it is quite common." McNeill (1897, 225) records it also 



