236 COLEOPTERA CHAP. 



There is but one genus, and for a long time only two or three 

 species were known, and were great rarities in collections ; in 

 the last few years the number has been raised to nearly forty. 1 

 They are remarkable beetles with oblong form, and a somewhat 

 metallic upper surface, which is much sculptured, and possesses 

 four yellow, smooth spots on the elytra. According to Mr. George 

 Lewis they are found feeding at the running sap of trees, but the 

 larvae are not known. Helotidae are peculiar to the Indo-Malayan 

 region (including Japan) with one species in Eastern Africa. 



Fam. 35. Thorictidae. Tarsi five-jointed, none of the joints 

 broad ; front coxae small, rather prominent, but not at all trans- 

 verse ; Jive visible ventral plates, all mobile ; metasternum very 

 slu>rt; antennae short, with a solid club. This little family, con- 

 sisting of the genus Thorictus, appears to be a distinct one, 

 though the structure has only been very imperfectly studied. It 

 is peculiar to the Mediterranean region, where the species live in 

 ants' nests. They appear to be on terms of great intimacy with 

 the ants ; a favourite position of the beetle is on the scape of the 

 antenna of an ant ; here it hooks itself on firmly, and is carried 

 about by the ant. Like so many other ants'-nest beetles, 

 Thorictidae possess tufts of golden hair, which secrete some 

 substance, the flavour of which is appreciated by the ants ; these 

 tufts in Thorictidae are situated either at the hind angles of the 

 pronotum, or on the under surface of the body on each side of the 

 breast ; Wasmann thinks that when the beetles are riding about, 



as above described, the ants have then 

 an opportunity of getting at the patches 

 on the under surface. 



Fam. 36. Erotylidae.--2Yfm five- 

 jointed, but with the fourth usually very 

 small, the first three more or less broad 

 and pubescent beneath. Antennae strongly 

 clubbed. Front and middle coxal accfa- 

 bula round, without angidar prolongation 

 FIG. u7.-Tri.toma lipustuiata. externally ; five visible ventral segments. 

 Erotyiidae. Britain. A, Larva This is now a large and important family 



(after Ferris) ; B, perfect Insect. ,, . . . . , . a 



ot about 1800 species, but it is chiefly 

 exotic and tropical, its members haunting the fungoid growths 



1 Ritsema, Catalogue of Helota, Notes Leydcn Mus. xiii. 1891, p. 223, and xv. 

 1893. p. 160. 



