80 



INTKODUCTION. 



This family is closely allied to the SiLPiiiDiE, in which it is 

 included by many writers ; it differs in the shape of the mentum, 

 the long and slender antennae, the very short metasternum, and 

 in the fact that the sternal epipleurae of the elytra are almost 

 obsolete or very little pronounced. Two genera are included in 

 this family. One of these, Leptinus, is found in dead leaves, 

 rotten wood, birds' nests, nests of field-mice, or even on the mice 

 themselves ; it also occurs in abundance in humble-bees' nests and 

 very rarely in ants' nests ; the true habits of the insect are there- 

 fore unknown. According to Sharp it has been suggested that 

 the natural home of Leptinus (two species of which occur in 

 Europe and one in America) is the bees'-nest, and that perhaps 

 the beetle merely makes use of the mouse as a means of getting 

 from one humble-bee's nest to another ; this, however, is some- 

 what contradicted by the fact that the allied American genus 

 Leptinillus is said by Riley to live on the beaver in company with 

 Platypsyllus. 



Family IS. TBICHOPTERYGIDiE. 



Very minute insects, the largest being under 2 millimetres in 

 length, and the smallest about a quarter of a millimetre ; antennce 

 with a three-jointed* more or less pronounced, club; maxilla? tri- 

 lobed ; tarsi three-jointed ; elytra sometimes covering the abdomen, 

 sometimes leaving the apex exposed ; wings f ringed on both sides by 

 long hairs. 



Fig. 40.— Wing of Trichopteryx. (After Matthews.) 



The members of this family are probably more or less abundant 

 throughout the greater part of the world, but they are usually 

 overlooked by reason of their extreme smallness, Nanosella fungi 



