LGCUSTID.E. ACRYDIUM. 33 



front; eyes globose^ slightly prominent; ocelli three; mouth placed in a 

 hollow in front of the sternum ; forehead with a grooved keel ; thorax cari- 

 uatedj its hinder margin produced to, or beyondj the extremity of the abdo- 

 men, and terminating in a point; elytra extremely short, appearing 

 distorted, and resembling oval scales ; wings sometimes ample, at others 

 rudimentary; abdomen soUd, conical, without an exserted ovipositor; legs 

 glabrous, anterior short, posterior longer than the body, with the femora 

 robust, and formed for leaping ; tibice spinulose, anterior with some spines 

 at the apex only ; tarsi without a cushion between the claws. 



The Acrydia are well known by their elongated prothorax, which 

 in one of the species extends backwards beyond the apex of the 

 abdomen, and in the others reaches almost to its extremity ; exclu- 

 sively of this prominent character, however, they may be distinguished 

 with facility by their minute elytra, and by the absence of the 

 pulvilli, or foot-cushions, between the claws ; their wings consist of 

 many longitudinal folds, and their costal edge is broadly coriaceous. 

 As to the number of species which are indigenous I am iitterly at a 

 loss to define them, as far too much uncertainty exists upon that 

 point : prior to the appearance of my Catalogue it was supposed that 

 there were four species found in Britain, but in the Catalogue I was 

 induced to sink two and add one, thereby leaving only three ; since 

 that time Mr. Curtis has published on the genus, and thinks there 

 may be four species — one new ; but, long anterior to the publication 

 of my Catalogue, Zetterstedt, in his Orthoptera Suecica (1821) 

 — a work I have only recently seen — described as different no less 

 than eighteen, all of which I possess; which Charpentier, in his 

 Horae Entomologica (1825) reduces to two, considering Zetterstedt's 

 first six species as one, and the other twelve as another. More 

 recently, Serville (in 1831) has made about eight species, corre- 

 sponding with specimens found in this country. In the face, there- 

 fore, of such conflicting opinions amongst authors who have expressly 

 devoted themselves to the study of the Orthoptera, viz. Zetterstedt, 

 Charpentier, and Serville, it would be ridiculous for me to attempt 

 the solution of the question, especially as I have scarcely attended to 

 the peculiarities of the genus beyond the occasional capture of some 

 of the more conspicuous varieties : I shall, therefore, merely intro- 

 duce as species those given in the second edition of my Nomenclature, 

 adding, from Zetterstedt, brief characters of the assumed varieties, so 

 far as I possess them. 



Mandibulata, Vol. VI., 31st May, 1835, e 



