MORGAN HEBARD 217 



The North American species of the Polyphaginae, owing to 

 Rehn's studies. -^'^'^ require but little revisionary treatment at the 

 present time. The much larger series now available, however, offer 

 an opportunity to ascertain further the relative values of the char- 

 acters which have been used and the degrees of variation found in 

 the different species. Moreover, numerous important male genitalic 

 characters have been found and are here described in detail. It is 

 evident that the genera here considered have a wide distribution in 

 Mexico; the small series available from that country have proven 

 most interesting and valuable, but, until extensive field work has 

 been accomplished in the regions south of the southern border of 

 the United States, no definite knowledge of the different species 

 distribution in that territory can be obtained. 



To the history furnished by Rehn in his revision, we may add that 

 the subgenera, described in that paper, have since been properly 

 raised to generic rank,'*-^^ while names, which have been proposed 

 for forms or races of three of the species, are here placed in their 

 proper synonymy. The Old World genus Polyphaga undoubtedly 

 includes more than one generic unit, as is shown by material in the 

 exotic collections now before us. 



None of the North American species have pulvilli or arolia. 



Key to the North American Species of the Polyphaginae {based on 



males^^^) 



A. Marginal and scapular fields of tegmina broad. Subgenital plate with 

 styles. (Supra-anal plate produced in a delicate bilobate projection. Cerci 

 jointed, evenly tapering. Cephalic femora with ventro-cephalic margin hau-y, 

 these hairs shorter distad, with a single heavy and elongate distal spine. Median 

 and caudal femora alone bearing a single dorso-cephalic genicular spine, this 

 spine stout and elongate. Cephalic tibiae bearing nine spines. Median and 



zm \ Revision of the Orthopterous Genus Honioeogamia. Proc. .Acad. Nat. Sci. 

 Phila., 1903, pp. 177 to 192, (1903). 



351 Caudell, Proc. U. S. Nat. Mus., xliv, p. 605, (1913). 



352 Within the orifice formed by the supra-anal and subgenital plates, which wc here 

 designate as the anal chamber, we find, in males of the present group, de.xtrad two plate- 

 like structures, here termed the dextro-dorsal and de.xtro-ventral plates, and sinistro- 

 dorsad a long, slender, chit inoiis process, here termed the genital hook. These structures 

 show features of very great specific diagnostic value and it is unfortunate that they can 

 seldom be observed without removing the subgenital plate. It is for this reason that 

 we term them concealed t;enitalia,in apposition to the wholly external or internal gcmtahc 

 features. 



MEM. .A.M. ENT. SOC, 2. 



