1916.] NATURAL SCIENCES OF PHILADELPHIA. 213 



These characters apply as well to the species of the Decorus Group 

 as they do to the semis Eotettix, which genus is, however, valid, as 

 it possesses other excellent characters. Morse correctly placed 

 auslralis beside attcnuatus, and the fifth species was hitherto unde- 

 scribed. Morse states that M. decoratus is closely related to M. 

 decorus and compares the two species in his original description; in 

 reality the two species belong to very distinct groups. 



The following analysis gives the important characters, found 

 principally in the male genitalia, of the present group. 



Important Color Characters. — The post-ocular fuscous stripe is 

 usually strongly, sometimes weakly continued, but always present 

 on the metazona in decorus, in the other species this stripe stops 

 abruptly at the principal sulcus. In the male sex of australis it is 

 very infrequently interrupted on the prozona by narrow oblique 

 faseise of the general color of the insect, 78 this species is the only one 

 of the group which has the sides of the abdomen wholly immaculate. 

 In nubilus the males have the dark markings on the sides of the 

 abdomen very large and the dorsum of the abdomen very dark. 



Furcula. — (Figured for all the species.) In decorus normally 

 widely divergent, slender, evenly tapering, acuminate and slightly 

 over one-third as long as supra-anal plate; in australis broad at base, 

 tapering to slender digitate tips which are due chiefly to an abrupt 

 mesal shoulder on the inner margins, one-third as long as supra-anal 

 plate and weakly divergent; in attenuatus weakly divergent, slender, 

 evenly tapering, acuminate and scarcely one-fourth as long as 

 supra-anal plate; in hebardi small knob-like plates with divergent 

 angulate apices, scarcely one-fifth as long as supra-anal plate; in 

 nubilus usually subparallel, scarcely tapering but very slender 

 fingers, less than one-third as long as the short supra-anal plate. 



Supra-anal Plate. — (Figured for all the species.) In decorus and 

 australis elongate, shield-shaped with sides meso-distad evenly 

 convex, the narrow percurrent median sulcus lying between sharp 

 but not high walls in the proximal portion of the plate, beyond 

 which are a pair of more distant, short, blunt ridges, which are evenly 

 convergent and almost join near the apex in decorus and at the apex 

 of the plate in australis, near the base of the plate on each margin 

 are very weak indications of a marginal plication. This plate is of 

 similar general structure in the other species, but shows the following 



78 Females of australis have this interruption almost always present, in sonic 

 specimen? it is very pronounced, leaving only traces of a fuscous band: such an 

 interruption is also found in this sex of .1/. nubilus. 



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