144 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL xx. 



a little contracted in the middle; furcula consisting of a pair of rather 

 distant, moderately slender, scarcely tapering, blunt, dark denticula- 

 tions, overlying the outer slopes of the subinedian ridges of the supra- 

 anal plate, and extending over the plate by only a little more than the 

 length of the last dorsal segment; cerci strongly cornpressed-bulLite 

 just beyond the base, the bullate portion broader than long and exte- 

 riorly very strongly and longitudinally convex, beneath sulcate, the 

 whole bullate portion abruptly narrowing and terminating in a com- 

 pressed, indirected, round-tipped, equal and short finger, falling a little 

 short of the tip of the supraanal plate; subgenital plate short, sub- 

 conical, and apically very broad by the abrupt rounded production of 

 the apical margin, the process of about equal height and posterior 

 breadth, entire. 



Length of body, male, 16 mm., female, 22 mm.; antennae, male, 6.5 

 mm. (est), female, 6 mm.; tegmina, male and female, 6 mm.; hind 

 femora, male, 10.25 mm., female, 12 mm. 



One male, 4 females. Souora, Mexico, A. Schott, Mexican Boundary 

 Survey. 



This species differs from the preceding two in the uniformity of the 

 pronotura, which does not expand posteriorly, and has a uniformly 

 sharp median cariua throughout; it is also lighter bodied and less 

 heavily marked. 



2. FLABELLIFEK SERIES. 



In this series, one of the few which combines macropterous and bra- 

 chypterous forms, the male prozona is feebly or distinctly longitudinal, 

 occasionally quadrate, the interspace between the mesosternal lobes of 

 the same sex varying from quadrate to half as long again as broad, or 

 somewhat more. The tegmina are either fully developed, though at 

 most but slightly surpassing the hind femora, much and irregularly 

 maculate; or half as long as the abdomen, heavily marked in the dis- 

 coidal field and subacuminate; or shorter than the pronotum and then 

 apically rounded. The length of the tegmina in each species, however, 

 is fixed. The hind tibiae are blue, with nine to eleven spines in the 

 outer series, or, in some brachypterous forms, red, with ten to thirteen 

 spines in the outer series. 



The supraanal plate is triangular, rather longer than broad, with no 

 or slightly developed transverse ridges. The furcula is minute or sub- 

 obsolete, except in a single instance where it is small. The cerci are 

 broad,' often excessively broad and nabellate, enlarging from the base 

 toward the middle, at least in the macropterous forms, rarely as much 

 as twice as long as broad, broadly rounded apically. The subgeuital 

 plate is short and broad, sometimes with a slight apical tubercle, the 

 lateral margins straight, the apical margin not elevated, or only in a 

 single instance. 



M. rileyanus is the most aberrant form, having very brief tegmma, 



