124 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. 



exceptional diversity for its twenty-two species, while ten series are 

 represented in the twenty species hitherto found in Canada. Nearly ^ 

 all the series have a large latitudinal distribution, the most limited 

 in this respect being: in the north, the utahensis series (three species), 

 from Washington and Alberta to Utah and Colorado, and the iudi- 

 gens series (one species), confined to Idaho ; and in the south the 

 lakinus series (three species), from Nebraska to central Mexico, the 

 impudicus series (one species), found only in Georgia and Mississippi, 

 the aridus series (three species), from Arizona to Jalisco, the puer 

 series (two species), found in Texas and Florida, and the inonmrus 

 series (three species), occurring in Illinois, Indiana, North Carolina, 

 and northern Mexico. 



ANALYTICAL KEY TO THE SPECIES OF MELANOPLUS. l 



A 1 . Tegniina conspicuously shorter than the abdomen, often no longer than pronotuin ; 

 furcula almost always developed feebly, generally no longer than the last dorsal seg- 

 ment from which it arises. 



1 l . Cerci of male-expanding from the base outward and bullate, abruptly tapering 

 and bent inward at tip ; subgenital plate of male abruptly elevated apically 

 (1. Lakinus series). 



c 1 . Interval between mesosternal lobes of male nearly twice as long as broad; 2 



of female fully half as broad again as long 1. marculentus (p. 139). 



c 2 . Interval between mesosternal lobes of male distinctly less than twice as long 



as broad; of female barely broader or not broader than long. 

 d 1 . Hind femora heavily biiasciate above and on the outer face; hind tibiae 



blue throughout 2. lakinus (p. 141). 



d 2 . Hind femora with feeble signs of bifasciation above only, if at all; hind 

 tibiae pale red, apically infuscated 3. sonorae (p. 143). 



6 2 . Cerci of male tapering in the basal half, usually from the very base, sometimes 

 throughout, usually laminate; subgenital plate of male of variable elevation 

 apically. 



c 1 . Cerci of male beyond the middle either equal or tapering, sometimes simply 

 styliform throughout, the tip usually more or less pointed but sometimes broad 

 or truncate ; metasterual lobes of male attingeut or subattingent. 3 



d 1 . Cerci of male very broad and shon, not more than twice as long as the 

 middle breadth, and broadly rounded at apex (2. Flabellifer series). 

 e\ Tegmina about half as long as the abdomen and much longer than pro- 

 notum; cerci of male not longitudinally sulcate apically. 

 f l . Interval between mesosternal lobes of male twice as broad posteriorly 

 as anteriorly, the inner margins of the lobes regularly divergent; interval 

 in female longer than broad; cerci of male but little longer than broad. 



7. discolor (p. 149). 



/ 2 . Interval between mesosternal lobes of male of nearly equal breadth in 

 front and behind, the inner margins of the lobes convex; interval in 

 female transverse; cerci of male nearly twice as long as broad. 



8. simplex (p. 150). 



1 By permission of the Assistant Secretary, this key has been issued in advance in 

 the Proceedings of the American Philosophical Society, XXXVI. No. 154. 



2 This interval is of various shapes in different species, cuneiform, clepsydral, or 

 rectangular, but for the purposes of this table the middle breadth is always taken. 



3 The cerci are faintly enlarged apically in M. meridio>iaUs and J/. tcalshii, which 

 come under this division. See also the note under the alternate category. 



