230 



COLEOPTERA 



Fam. 26. Histeridae. — Very compact beetles, tuith very hard 

 integument, short, heut antennae, with a very compact club : oio 

 hyp)oglottis. Elytra, closely ap2>li€(l to body, but straight behind, 

 leaving tioo segments exposed. Abdomen with Jive visible ventral 

 segments ; with seven dorsal segments, all hard. Front coxae 

 strongly transverse, hind coxae loidely separated. The extremely 

 compact form, and hard integument, combined with the peculiar 

 antennae— consisting of a long basal joint, six or seven small 

 joints, and then a very solid club of three joints covered with 



minute pubescence — render 

 these Insects unmistakable. The 

 colour is usually shining black, 

 but there are niunerous depar- 

 tures from this. The way in 

 which these Insects are put 

 together so as to leave no chink 

 in their hard exterior armour 

 when in repose, is very remark- 

 able. The mouth - parts are 

 rather highly developed, and 

 the family is entitled to a high 

 rank ; it consists at present of 

 about 2000 species ; ^ in Britain 

 we have about 40. The larvae 

 are without ocelli or lal)rum, 



Fig. IIQ.—Plcdysoma depressum. Europe, hut have well-developed mandi- 

 A, Larva (after Schicidte) ; B, perfect , , ,, ■, i ii • i 



i,isec);_ / ' r |j|gg^ ^j^Q second and thu'd 



thoracic segments being short, 

 the ninth segment of the abdomen terminal, w^ith two distinctly 

 jointed cerci.^' Histeridae are common in dung, in carcases, decay- 

 ing fungi, etc., and some live under bark — these being, in the 

 case of the genus Hololepta, very flat. Some are small cylinders, 

 elaljorately constructed, for entering the burrows of Insects in 

 wood (Trypa?iacns) ; a certain nund)er are peculiar to ants' nests. 

 Formerly it was supposed that the Insects were nourished on 

 the decaying substances, but it is now belie^'ed, with good reason, 

 that they are enunently predaceous, in both larval and imaginal 



^ The family was monographed by the Abbe de Marseul in Ann. S'oc. cnt. France, 

 1853-1862, but great additions have been made since then. 



- For characters of larvae of various genera, see Perris, Zanrs, etc. p. 24. 



