416 FAMILY VI. ACRIDIDJE. THE LOCUSTS. 



Scudder (1897, 182) says of atlanis: "Next to M. spretus this 

 is our most destructive locust, and east of the Mississippi prob- 

 ably the only one ever doing much damage. Its injuries, how- 

 ever, are not for a moment to be compared with those inflicted by 

 M. spretus, for, though possessing good powers of flight and on 

 rare occasions known to migrate in swarms, its injuries can only 

 be classed as local, and they are never so serious as those inflicted 

 by M. spretus ; nevertheless they are by no means slight, and im- 

 mense destruction of grain is to be laid at its door. While it oc- 

 curs over an extended territory, it appears to be partial to hilly or 

 mountainous regions; it seems also to prefer a wooded or mixed 

 country to the open prairies or plains." 



In Old Mexico atlanis is replaced by M. me.rica.nus Sauss. 

 (1861, 160), of which Hebard (1917b, 271) considers atlanis a 

 northern race. He states that individuals from there show both 

 red and glaucous tibia?, the glaucous type being much more fre- 

 quently encountered in Mexico than in the United States. 



Series IX. THE FLAVIDUS GROUP. 



Since this group is represented by but a single species, its 

 principal diagnostic characters are given in the key and in the 

 specific description and their repetition is unnecessary. 

 194. MELANOPLUS KLAVIDUS Scudder, 1879, 74. Blue-legged Locust. 



Size slightly above the medium for the genus, the females one-third 

 the larger; form slender. Pale olive-brown above, greenish-yellow beneath. 

 Face sometimes mottled with fuscous; the black postocular stripe, when 

 present, usually narrow and reaching only to metazona, often stibobsolete, 

 sometimes widened and extending along the sides of disk as well as those 

 of pronotal lobes. Antennse uniform dull yellow. Tegmina with a vague 

 narrow median pale stripe, this often with a few small fuscous spots. 

 Hind femora dull yellow, the upper half of outer face dusky, the upper 

 and inner faces usually with two oblique dusky bars. Hind tibia? blue, the 

 spines white, tipped with black. Interocular space slightly wider than 

 first antennal joint, male, as wide as frontal costa, female. Fastigium 

 feebly declivent, strongly sulcate, male, feebly concave, female. Frontal 

 costa prominent, broadly and rather deeply sulcate at and below the ocellus. 

 Disk of prozona slightly convex, the sides parallel and rounded into lateral 

 lobes; of metazona nearly flat, the sides feebly divergent, hind margin ob- 

 tuse-angulate; median carina low, distinct on metazona, often vague on 

 prozona. Tegmina narrow, slightly surpassing tip of abdomen, male, 

 reaching tip or base of ovipositor, female. Supra-anal plate of male 

 broadly triangular, the apical third elevated and abruptly subacute. Fur- 

 cula as described in series key, their tips ending in slightly widened knobs. 

 Cerci with base broad, triangular, the apical two-thirds slender, less than 

 half as wide as base, incurved, the sides nearly parallel, tip bluntly 

 rounded (Fig. 141, cJ.) Subgenital plate scoop-shaped, well rounded above, 

 the tip slightly produced. Length of body, $ , 2126, $ , 2532; of anten- 



