3'38 CLAViCouNiA. [Byrrhus. 



in Europe ; no species appear to be fouml in tropical countries, although 

 representatives occur as far north as Greenland, and as far south as the 

 Straits of Magellan ; they are round, very convex insects, and have very 

 strongly retractile legs, so that they can contract tiiemselves into a ball, 

 and thus avoid the attacks of their enemies. 



For the following table I am chiefly indebted to Reitter, and it will 

 be found easy to distinguish the species with its help ; the first two or 

 three species are exceedingly variable in colour ; in fact, no less than 

 thirteen named varieties of B. fasciatus and six of B. iiilula are men- 

 tioned in the last European catalogue : I have regarded B. Benny i as a 

 variety of the last mentioned species, as it is evidently too closely 

 allied to it to be regarded as distinct; in fact, Stephens himself (111. iii. 

 136) says that " it may only be a variety of the foregoing," and he cer- 

 tainly cannot be accused of too much synthesis ; the species of Byrrhus 

 soon get rubbed, and fresh specimens have a very different appearance to 

 those that have been out for some time. 



I. Elytra with the pubescence usually sericeous or totnentose, 

 without distinct rows of raised setae ; furrows to receive legs 



less deep; length 6-10 inm. {Byrrhus, i. sp.) 

 i. Lensjth 7-10 mm. ; form longer or shorter oval, with sides 

 of elytra subparallel, broadest at or behind middle; fore- 

 head much more finely punctured than clypeus. 



1. Under-side clothed with very thin greyish pubescence; 



anal segment in both sexes with three impressions . . . B. ptlula, L. 



(v. Denny i, S;cpli.) 



2. Under-side clothed with moderately thick yellowish pubes- 

 cence ; anal segment in both sexes without impressions . B. FASCiAXCfS, F. 



ii. Length 6-6^ mm. ; form short and bi-oad oval, with sides 

 of elytra rouiuknl and widened, broadest before middle; 

 forehead and clypeus equdly punctured B. doesalis, F. 



II. Elytra with more or less distinc't lovvs of raised setfe ; furrows 

 to receive legs, especially the hinder pair, very deep; length 



not exceeding 4 mm. {Curimus, Er.) B. murinus, 111. 



S. pilula, L. Oblong oval, black, clothed with tomentose and 

 somewliat sericeotis pubescence, which is very variable in colour and dis- 

 tribution ; head large, finely punctured, clypeus strongly punctured, 

 antennae blackish with joints 2-4 reddish, last joint of maxillary palpi 

 oval, truncate ; thorax finely punctured, as in the other species, much 

 narrowed in front ; elytra with very fine punctured striae, interstices 

 flat ; legs pitchy-black, pitchy-red, or reddish ; under-side thickly 

 punctured, rather scantily pubescent, anal segment with three impressions; 

 the pubescence on the upper surface is usually brown, that on the 

 scutellum being mostly black, and the elytra have the alternate 

 interstices furnished with interrupted bands of black velvety pubescence, 

 the spaces between being often more or less golden ; when the specimens 

 are at all rubbed, as they usually are, the character of the pubescence is 

 entirely altered. L. 7-10 mm. 



