HISTEEIDiE. 



9] 



Family 25. HTSTE111D/E. 



Compact, hard, usually shining insects ; antennas geniculate, as a 

 rule received in grooves beneath the pronotum, with a long basal joint, 

 and a six- or seven-jointed funiculus, the last three or four joints 

 forming an abrupt club ; mandibles strong, maxiUce bilobed ; pro- 

 notum closely applied to the elytra ; elytra truncate, leaving the last 

 two segments of the abdomen uncovered; abdomen with jive visible 

 ventral segments and seven dorsal, cdl hard; legs short and stout, 

 retractile ; tarsi short, usually Jive-jointed (posterior pair rarely 

 four-jointed); anterior coxae transverse, posterior coxa' widely sepa- 

 rated ; upper surface usually very smooth and shining, sometimes 

 dull and with raised furrows. 



This is a very large and well-defined family, containing, as at 

 present known, about 1(500 to 1700 species. The great majority 

 of them are of a shining black colour with strongly engraved 

 striation, but in the case of Hister and Saprinus a few species 

 have bright red spots or markings, and some are more or less 

 metallic. The shape is very variable and the variation is evidently 

 due to habitat.. 



The species of Hister and its allies, which live in dung and 

 decomposing carcases, are convex and very much polished, so that 

 they always appear clean ; they are often, however, much infested 

 by Acari which secure a firm hold on their bodies. Hololepta and 

 Platysoma, which live under the bark of trees, have the bodies 



Fig. 44. — Hister bengcdensis. Fig. 45. — Hololejyta elongata 



(and side view). 



much flattened, while Trypanaus, Teretrius, etc., which enter the 

 burrows of wood-boring insects, are quite cylindrical and eminently 

 adapted for their mode of life. The Histeeidye have usually 

 been considered to be for the most part feeders on dung, dead 

 animals, etc., but it is probable that they are for the most part 

 predaceous, both in the larval and perfect state, and that they 

 inhabit decaying matter, not because it is their food, but because 

 of the Dipterous larva?, etc., which it nourishes. Saprinus 

 virescens has long been known as feeding on the larvae of Phcedon, 

 on Sisymbrium, etc., and Hister helluo has been recorded as feeding 



