GEOLOGICAL SUEVEY OF THE TEERITOEIES. 439 



purpurascens. I had not then seen a specimen of A. simplex^ Hald. ; nor 

 had I seen the excellent synopsis of the European species ot Thamno- 

 trizon by Brunner de Wattenwyl, (in Verhandl. Zool.-Bot. Vereius in 

 "Wieu, XI, 1861,) the articles by Yersin, (Ann. Soc. Ent. Franc, 3d ser., 

 Tom. yi and VII,) or Fieber's Synopsis, (Lotos, 1853.) Now, having 

 specimens of all the species {simplex, SaXdemannii, purpurascens) before 

 me, and access to the works named and those of Serville, Fischer, &c., I 

 iind that while I was correct in separating the species, I was mistaken 

 in the disposition made of them, and, as a matter of course, in my 

 emendation of the generic characters. 



The genus Anahrus was formed by Haldeman for the reception of his 

 A. simplex, hence in emending the original description its characters 

 should be such as to embrace the species on which it was founded. A 

 more thorough examination of the generic characters of T'hamnotrizon 

 as given by the various authors; a comiDarison of the figures by Brun- 

 ner de Wattenwyl,Vou Fraueufeld, Fischer, &;c., and personal inspection 

 of some specimens which I am satisfied belong to this genus, discovered 

 the past season, lead me to the conclusion that the arrangement and 

 number of spines on the front of the anterior tibite is a true normal 

 character, although having some slight exceptions, (for T. /a??aa? appears 

 from the figure in Verhandl. Zool.-Bot., XI, 1861, PI. 10, to vary from 

 this type.) As A. simplex mid purpurascens have two rows of spines on 

 the front of the anterior tibiae, (one 4-5, the other 2-3, making in all QS,) 

 they cannot belong to this genus, but should remain where originally 

 placed. A. Haldemannii, having the |Drosternum very distinctly bispinose, 

 must be placed in some other genus, and even without this distinction 

 there are other differences which will remove it from generic association 

 with these species. I am not well satisfied where it should go, but place 

 it provisionally in Pterolepis, Fisch., (not Serville,) with which it appears 

 to be most nearly, allied. 



There is much confusion in regard to this group of genera. Fischer 

 (Orthop. Europ.) separates Tliamnotrizon from Pterolepis of Eambur, 

 placing the species without i)rosternal spines in the former, leaving 

 those with spines in the latter ; while Serville places the species without 

 prosternal spines in Pterolepis. Fieber, following Serville, places the 

 unarmed species in Pterolepis and forms a new genus — Ehacocleis— for 

 those which are spined. Yersin (Ann. Soc. Ent. Franc, 3d ser., VI) 

 describing Pterolex)is alpina gives the spines as a character. Orcliesticus 

 of Saussure (Eev. Mag. Zool., 2d ser., XI., 1859, p. 201) comes very close 

 to this, the chief difference being in the mesosternum. Brunner de 

 Wattenwyl appears to follow Fischer in regard to Tliamnotrizon, but 

 on the other hand adopts the Bhacocleis of Fieber for his spined species, 

 omitting Pterolepis altogether. He forms a sub-genus in Becticus, 

 which he names Psorodonotus, to which he removes Pterolepis (ilpina, 

 Yersin. 



In the midst of such confusion, which Walker has increased by the 

 formation of several too closely-allied genera, it is -difficult to place a 

 somewhat abnormal species. It is probable Dr. Scudder will clear up 

 this difficulty in his anxiously looked- for work on the Ortlioptera ; there- 

 fore for the present I have adopted the following arrangement as the 

 best I can do with the materials I have at hand. I would not venture 

 to take this step if it were not necessary to adopt some consistent ar- 

 rangement of the new species I obtained during my recent visits to the 

 Bocky Mountains. 



Discarding i?/i«cocZm, Fieb.; retaining P^eroZep^s, Fisch., (Not. Serv. ;) 

 and restricting the other genera to their true limits, the genus Anahrus 



