184 PROCEEDINGS OF THE ACADEMY OF [June, 



A REVISION OF THE GENERA AND SPECIES OF THE GROUP MOGOPLISTII 



(ORTHOPTERA; GRYLLID.E) FOUND IN NORTH AMERICA 



NORTH OF THE ISTHMUS OF PANAMA. 



BY JAMES A. G. REHN AND MORGAN HEBARD. 



The group Mogoplistii forms a division of the subfamily Myr- 

 mecophilince and comprises eleven genera and over fifty species 

 described from localities well distributed over the warmer regions of 

 the earth. All of the species are of small size, very delicate and 

 covered with minute, easily abraded scales, for which reasons they 

 appear to have been but little collected, and in consequence most of 

 the species were described from but little and often badly damaged 

 material. 



In studying an extepsive series of North American specimens of 

 this group, we found it necessary to go so deeply .into the relationship 

 of the various genera and species that it became incumbent on us to 

 analyze all of the genera described to this date, to construct a new 

 key for all of the genera, and also erect four new genera. In addition 

 to this we were confronted with a great amount of confusion in regard 

 to the characters and extent of certain genera and also some com- 

 plicated specific synonymy. As these facts are best discussed in a 

 chronological sequence, we have summarized the history of the names 

 here treated. 



History. 



In 1839, Serville erected the genus Mogoplistes 1 on the species 

 M. brunneus from southern Europe [Sardinia]. Guerin, in 1844, 

 described the genus Ornebius, 2 basing it on two new species, 0. 

 xanthopterus, from Mauritius, and 0. nigripalpis, from Pondicherry, 

 the former of which has been selected as the genotype by Kirby. 

 The same author, in 1849, erected the genus Ectatoderus, 3 on a new 

 species E. nigriventris, from Abyssinia. In 1855, Costa based a new 

 genus Arachnocephalus* on a species from Naples, this author being 



1 Hist. Nat. Ins. Orth., p. 357. 



- Iconogr. Regne Anim., Ill, p. 331. 



3 In Lefebre, Voy. en Abyss., VI, p. 336, Ins. pi. VI, fig. 3. 



4 Fauna Nap., Grill., p. 41, pi. IX, fig. 5. We are unable to quote this reference 

 from the original work as, unfortunately, our copy is incomplete, lacking among 

 ethers the reauisite naee. 



