238 FAMILY VI. ACRIDIM3. THE LOCUSTS. 



era Illinois Hart (1907, 231) reports it as "abundant in all blow- 

 sand areas." R. & H. (1906, 372) mention it as one of the most 

 plentiful species encountered in Montana and Colorado, occurring 

 "in many of the arid localities and swarming on the prairies." 

 Morse (1907, 32) calls it a "widely distributed species, locally 

 common, especially on sandy soil with a sparse clothing of herb- 

 age." while Somes (1914, 31) says that in Minnesota it sometimes 

 occurs in tall or close grasses, when it endeavors to escape by div- 

 ing headlong to the ground and crawling among the stems. 



The Indiana and Chicago specimens (arenosus Hancock) are 

 somewhat smaller and darker than those from Lincoln, Neb. 

 (typical scudderi Brun.), but present no structural differences 

 worthy of placing them as distinct; while Gillette and Bruner 

 (1904) have doubtfully, and R, H. (1906) more certainly ex- 

 pressed their opinion that scudderi is only a synonym of deorum. 



Tribe V. MECOSTETHI. 



Species of rather large size, having the head horizontal ; ver- 

 tex short, its disk with a distinct median cariua; foveohp very 

 small, triangular, sometimes almost obsolete, situated on the base 

 of each of the raised margins of vertex; face subvertical; lateral 

 carinse of pronotum usually less distinct than the median one, 

 sometimes cut by all the sulci; tegmina well developed, always 

 surpassing the abdomen, their intercalary vein stout, nearer the 

 ulnar than the radial vein; inner apical spurs of hind tibia? sub- 

 equal. But one genus represents the tribe in our territory. 



I. MEcosTETi-ius 39 Fieber, 1852, 1. (Gr., "long" + "breast.") 

 In addition to the characters above given, our species of this 

 genus agree in having the vertex horizontal, its sides raised and 

 apex usually slightly rounded; antenna? filiform, equal to, female, 

 or longer, male, than head and pronotum together; frontal costa 

 wide, sulcate, with sides divergent below the ocellus; pronotum 

 with disk rugose, median carina sharp, cut in or in front of mid- 

 dle by the principal sulcus, metazona as long as or longer than 

 prozona, its hind margin obtusely angled; lateral lobes about as 

 high as long, their front margins perpendicular, hind ones slightly 

 oblique, lower ones with front half ascending; tegmina of male 



39 This generic name, which has been in common use in this country, has been recently 

 replaced by Kirby, R. & H. and others by Arcyptera, Hebard stating '(Ms.) that the type 

 of Mecostethus is grossus, which is generically distinct. Kirby (1910, 144) makes alliaceus 

 Germ, the type of Mecostethus. As both Brunner (1893, 123) and Burr (1904, 321) make 

 the presence of the intercalary vein in Mecostethus the principal character separating that 

 ?enus from Arcyptcra and allied genera, and as this vein is present and prominent in 

 all our three species and has been used by Scudder, McNeill and others as the principal 

 differential character of Mecostethus, I retain that generic name in preference to Arcyp- 

 tera in which, according to Burr, the intercalary vein is absent. 



