PLcdcrina;.'] STAPiiTLiNiDiE. 297 



b. Prostornnm only slightly devoloped above tlie 



frout poxas LlTnoCHAEls, Lac, 



B. Tliornx strongly contracted in front, more or less 

 orbicular. 



a. Posterior tarsi nearly as long as tibiao, joints 



1-4 decreasing gradually in length .... Stilicus, Latr. 



b. Posterior tarsi short, joints 1— i nearly equal in 



length SCOP^US, Er. 



11. Penultimate joint of tarsi bilobcd. 



i. Penultimate joint of tarsi without membrane beneath ; 



species large P^DEETIS, F. 



ii. Penultimate joint of tarsi with pale membrane beneath ; 



species small SuNlUS, Steph. 



ZiATHIlOSIUZVZ, Gravenhorst. 



This is a large and almost cosmopolitan genus containing at presont 

 between 150 and 200 species; these are chieHy confined to temperate 

 and cold regions ; twenty-five species, however, are known from the 

 Amazon valley; they differ very much in size and general appearance, 

 Init the attempts to break the genus up into sub-genera have not hitherto 

 been very satisfactory ; they occur in moss, under stones, in vegetable 

 refuse, at roots of grass, &c. ; the sexual characters are very peculiar, the 

 males of many species being furnished on the middle of the seventh 

 ventral segment with two longitudinal tufts or crests of dark, erect, pubes- 

 cence, enclosing between them a larger or smaller smooth space ; the 

 projecting lobes of the segment of armature also present important 

 differences, but these are hard to describe, and the student of the group 

 is referred to Mulsant and Eey, Brevipennes, Pcderiens, 1878, Plate II., 

 where the male characters of most of our species are figured. There are 

 fifteen British species which may be disting\;ished by the following charac- 

 ters ; it must, however, be remembered that the table here given is a 

 purely artificial one ; a more strictly scientific arrangement is given by 

 Mulsant and Rey (I.e. p. 30, &c.), but it is one that will only cause great 

 confusion to most workers ; many species of the genus present two dis- 

 tinct forms ; in one of these the insect is winged and has longer elytra ; 

 in the other it is apterous or has more or less rudimentary wings, and the 

 elytra are shorter and more sparingly punctured. 



1. Head usunlly narrower than, at most as broad as, or 

 very slightly broader than, thorax. 

 i. Elytra confusedly punctured. 



1. Elytra red with base more or less broadly black, 

 sometimes entirely red with base slightly fuscous. 

 A. Antennae with joints moderately stout ; length 

 6^-9 mm. 

 a. Head diffusely punctured on disc, more 

 thickly at sides ; antennaj rather long ; 

 size larger, 

 a.* Head subtrinngular, rather short, a little 

 broader behind tlian near eyes ; red 

 colour of elytra bright. 



