334" NATURAL ARRANGEMENT OF INSECTS. 



with a similar structure, has the four first joints of the 

 tarsi with a long membranous appendage ; and in 

 Tillus, the sexes of one have heen considered generally 

 distinct species. In those which have but four dis- 

 tinct joints to the tarsi, there is a greater uniformity in 

 the general structure of the antennae,, although Eno- 

 plium has its three terminal joints separated and ser- 

 rated. Some of the species of Clerus are parasites in 

 the nests of certain mason bees ; and the genus Thana- 

 simus occurs upon felled trees and timber, its larva 

 preying upon those of many of the wood-feeding ge- 

 nera, as Apate, Bostrichus, Anobium, &c. They are 

 all very active insects ; and some of the latter, in the 

 distribution of their colours, and general form, have a 

 remarkable resemblance to the hymenopterous Mutilla, 

 and whence they have derived their specific names. 

 All these insects have the head rather wider than the 

 thorax ; the latter cylindrical, and constricted at its 

 base, or swoln about the centre ; although some, as Co- 

 vynetes and Necrobia, have the sides of the latter slightly 

 margined. These are found, usually, among heaps of 

 bones, or upon dry carrion ; and one of the latter is 

 celebrated for being the cause of saving Latreille's life 

 during the sanguinary period of the French revolution ; 

 in as far as the circumstance of its capture, in his pri- 

 son cell, interested, through the medium of the surgeon 

 that attended him, some influential scientific men, who 

 stayed his debarkation to the colonies in a ship that 

 . was atrociously foredoomed to perish, with its cargo of 

 transports, almost within sight of their native land. The 

 largest species occur in the Mexican genus Cymatodera, 

 and the universal Opilus. Europe is rich in species of 

 the family ; but New Holland appears to be their me- 

 tropolis, if we may judge from the numbers, and the 

 forms, we have seen recently imported thence. Very 

 many genera are still uncharacterised in this interesting 

 group. [(290296.) W. E. Sh.] 



