140 FAMILY VI. ACRIDID^E. THE LOCUSTS. 



with fuscous; apical margin of cerci subtruncate, above 

 less prolonged, with angle more rounded (Fig. 148, b.) 



206a. SYMMETRICUS. 

 cc. Cerci distinctly forked or deeply emarginate. 



e. Upper fork of cerci slightly longer than the lower one (Fig. 

 148, c) ; anal field of tegmina grayish-yellow; discoidal field 

 darker with numerous small fuscous spots or blotches. 



207. FURCATUS. 



ee. Lower fork of cerci longer, with apex more narrowly rounded, 

 than the upper one; discoidal field of tegmina a uniform 

 fuscous-brown. 207a. PEGASUS. 



205. MELANOPLUS DIFFERENTIALS (Thomas), 1865, 450. Differential 

 Locust. 



Very large and robust, the females distinctly the larger. Color usually 

 a nearly uniform dark brownish-green or olive-brown above, bright to dull 

 yellow beneath. Face olive-green, often with oblique fuscous streaks. 

 Pronotum with transverse sulci and pleural incisions black. Tegmina 

 olive-brown, immaculate. Metapleura yellow; sides of basal segments of 

 abdomen in part black. Hind femora either dull or bright yellow, the 

 outer face with narrow black marks arranged herring-bone fashion; upper 

 inner face with three oblique black bars; lower face yellow; knees black, 

 their lower outer lobes bright yellow. Hind tibiae yellow, with a narrow 

 black basal ring, the spines black. Interocular space twice or more as 

 broad as first antennal joint; fastigium gently sloping, broadly but not 

 deeply concave. Frontal costa broad, but narrower than interocular space, 

 broadly and shallowly sulcate at and below the ocellus, male, less distinctly 

 so, female. Disk of pronotum flat or nearly so; median carina distinct 

 and sharp on metazona, less distinct but visible on front half of prozona, 

 the prozona subquadrate, slightly longer than the finely rugulose metazona. 

 Tegmina exceeding tips of hind femora in both sexes, the narrowest apical 

 portion about half as wide as the broadest basal portion. Supra-anal plate 

 very broad, the sides of apical third rounded and thence strongly oblique 

 to the obtuse apex; margins upcurved to form broad, shallow con- 

 cavities each side of the deep, percurrent median sulcus. Cerci as in key 

 and Plate IV, p. Subgenital plate short, broad, the middle of apical margin 

 thickened, slightly prolonged upward, usually entire, rarely feebly notched. 

 Upper valves of ovipositor short, stout, tips strongly upcurved, outer mar- 

 gins distinctly crenulate. Length of body, <$ , 28 34, 9, 34 44; of anten- 

 nae, $, 1618, 9, 1516; of pronotum, $,1, 9, 10; of tegmina, $, 2932, 

 9, 3235; of hind femora, $, 18.520, 9, 2123 mm. (Fig. 149.) 



This is the largest and at the same time one of the most com- 

 mon and destructive of our Melanopli. It occurs throughout In- 

 diana, reaching maturity in the central portion about July 25th, 

 and may be found in favorable seasons until December 1st. In 

 late autumn the females are always worn and bedraggled, while 

 many of the males are bright colored and evidently freshly moult- 

 ed. . The species becomes darker with age and those which mature 

 in autumn are darker than those of mid-summer, often in great 



