INSECTA MADERENSIA. 27 



Carahidce presents so few, and such sliglit modifications in the oral organs that it 

 is positively necessary to depend in a great measm-e on outward details even for 

 generic purposes, unless we are content to amalgamate many grovips which are 

 universally received. As some compensation however for the deficiency in struc- 

 tm'al differences, the Frlstonychi are most easily separated from the Calathi exter- 

 nally, being not only larger and darker insects (their colour being for the most 

 part black, with a violet or pm-plish tinge), and with much longer legs, but their 

 prothorax is in every instance more or less narrowed behind, instead of (as is the 

 case with the latter) in front. The Fristoiii/cM are of a more darkling nature 

 than the Calathi, being, like the genus Spliodrus, often found in houses, or at any 

 rate in the immediate vicinity of habitations : and even when this is not the case, 

 the same kind of propensity seems to be indicated by the peculiarity of the localities 

 which they select, — a marked preference being sho^vn for caves, and other partially 

 sheltered spots, beneath the stones in which they frequently delight to congregate. 



19. Pristonychus alatus, WoU. 



P. alatus, niger, prothorace subcordato, elytris subpuuctato-striatis obscure cyaneis, antennis pedi- 



busque plus minusve picescentibus, tibiis in utroque sexu rectis. 

 Long. Corp. lin. 6-9. 



Habitat sub lapidibus in colliuis Maderpe maritimis atque in cavernis tufae, sat frequens : ad Ribeiro 

 Secco prope ui'bem Funclialensem d. 13 Feb. coUegit cl. Dom. Heer, necnon baud procul a 

 Sancta Cruce egoniet deprebensi : in insula Portu Sancto usque ad maris litus descendit, qua 

 prope oppidum mense Decembri exeunte a.d. 1848 copiosissime legi. 



P. dark piceous-black, and very sligbtly shining; above witb an obsciu'e bluish tinge, especially on 

 the elytra, where it is occasionally comparatively brilliant. Head and prothorax nan-ower than 

 the elytra ; the former with two deep longitudinal impressions on the forehead ; the latter sub- 

 cordate, with an obscure dorsal channel, and with a deep longitudinal fovea on either side at the 

 base. Elytra striated, the striae being most obscurely punctured. JVings greatly developed. Legs 

 palpi and antenna more or less picescent ; the apex of the last, and the tarsi, brownish. Tibia, in 

 both sexes, straight, and very slender. Claws distinctly serrated. 



Eor a long time I had conceived the present JPristonychus to be identical Avith 

 the European P. subcijaneus, for it bears so strong a resemblance primd facie to 

 that insect, that, without exainination, it is not easy to separate the two. A more 

 careful inquiiy however has since convinced me that the Madeiran species is un- 

 questionably distinct, since the structui'al differences wliich it exhibits are such as 

 can scarcely be accounted for by the agency either of isolation or of latitude. Thus, 



and by most entomologists after him, as " ligula apice rotmidata." In real troth the hgula of Calathus 

 is as much ti-uucated in front as that of Pristonychus and of the allied genera ; but the fact of its para- 

 glossae being short, and consequently not projecting at the angles, gives the entire labium a somewhat 

 roimded appearance anteriorly. 



E 2 



