POLYMORPHA LEPTINIDAE SILPHIDAE 22 1 



ill curious places, including the nests of mice and bumble-bees. 

 In America it has been found on the mice themselves by Dr. 

 Eyder, and by Kiley in the nests of a common field-mouse, 

 together with its larva, which, however, has not been described. 

 The allied genus Leptinillus is said by Eiley to live on the 

 beaver, in company with Platypsylhis} It has been suggested 

 that the natural home of the Leptinus is the bee's nest, and 

 that perhaps the beetle merely makes use of the mouse as a 

 means of getting from one nest of a bumble-bee to another. 



Fam. 15. Silphidae. — The mentum is usually a transverse 

 plate, having in front a memhranoiis hypioglottis, which hears the 

 exposed labial palpi, and immediately behind them the so-ealled 

 iilohed ligula. The anterior coxae are conical and contiguous : 

 p)rothoracic ejjimera and ep)isterna not distinct. Visible abdomi- 

 nal segments usually five, but sometimes only four, or as many as 

 seven. Tarsi frequently five-jointed, but often with one joint less. 

 Mytra usually covering the body and free at the tips, but occasion- 

 cdly shorter than the body, and even truncate behind so as to expose 

 from one to four of the dorscd plates ; but there are at least three 

 dorscd plates in a membranous condition at the base of the abdomen. 

 These beetles are extremely diverse in size and form, some being 

 very minute, others upwards of an inch long, and there is also 

 considerable range of structure. In this family are included 

 the burying-beetles (JVecrophorus), so well known from their habit 

 of making excavations under the corpses of small Vertebrates, 

 so as to bury them. Besides these and Silpiha, the roving 

 carrion -beetles, the family includes many other very different 

 forms, amongst them being the larger part of the cave-beetles 

 of Europe and ISTorth America. These belong mostly to the 

 genera Bathyscia in Europe, and Adelofs in North America ; but 

 of late years quite a crovvd of these eyeless cave-beetles of the 

 group Leptoderini have been discovered, so that the European 

 catalogue now includes about 20 genera and 150 species. The 

 species of the genus Catopomorphics are found in the nests of 

 ants of the genus Aphaenogaster in the Mediterranean region. 

 Scarcely anything is known as to the lives of either the cave- 

 Silphidae or the myrmecophilous forms. 



The larvae of several of the larger forms of Silphidae are well 

 known, but very little has been ascertained as to the smaller forms. 



1 Insect Life, i. 1889, pp. 200 and 306. 



