730 CLASS IV. INSECTA. 



Fam. 34. Helotidae. Anterior and middle coxal cavities round, coxae 

 wide apart. This family is allied to the Nitidulidae but differs in the struc- 

 ture of the coxae. There is but one genus, found in Japan, the Malay 

 peninsula and East Africa. 



Fam. 35. Thorictidae. Antennae short, clubbed. Front coxae small 

 and not transverse, metasternum very short. Tarsi with five segments. Only 

 one genus Thorictus found in Ants' nests around the Mediterranean. 



Fam. 36. Erotylidae. Tarsi apparently four-segmented with the first 

 three joints broad and pubescent ; there is however a minute fifth 

 segment. Antennae clubbed. Coxal cavities round. The family is large, 

 mainly found in hot climates ; the members of it feed on fungi. Tritoma 

 is British. 



Fam. 37. Mycetophagidae. Tarsi slender, all four-segmented, except in 

 the males where only three segments are found in the anterior limbs. 

 Coxae oval not imbedded. Small beetles often with red or yellow dots, 

 found amongst fungi, especially such fungi as attack timber. Widely 

 distributed. Litargus is British. 



Fam. 38. Coccinellidae. Four-segmented tarsi, but only three seg- 

 ments visible easily as the third is sunk in the second ; first and second pubes- 

 cent. Antennae short and clubbed. Pronotum largely concealing head. 

 The lady-birds, Coccinella, are a largish family of some 2,000 species. The 

 larvae are oval with tubercles bearing hairs ; they devour plant-lice and 

 scale-insects, etc. The beetles are rounded or oval and often brightly 

 ornamented. 



Fam. 39, Endomychidae. Tarsi really four but apparently three- 

 segmented as in the Coccinellidae ; but the clubbed antennae and the 

 legs are longer. An exotic family with few representatives in cold climates. 

 They live on plants especially cryptogams. 



Fam. 40. Mycetaeidae. Four-segmented tarsi usually slender. An- 

 terior and middle coxae globular. A small family of small fungus-eating 

 insects found chiefly in the Holarctic region. Mycetaea hirta is common 

 in London cellars. 



Fam. 41. Latridiidae. Three-segmented tarsi, front coxal acetabula 

 round. Pronotum usually narrower than elytra. Minute but widely 

 distributed and very numerous beetles, with weakly developed mandibles. 

 The larvae are soft, oval in outline , and bear hairs. They live in veget able 

 debris and eat fungi. Latridius is British. 



Fam. 42. Adimeridae. Four-segmented tarsi, but as the second and 

 third segments are concealed between the fourth and the broad basil joint, 

 they are apparently only two segmented. This family contains but one 

 genus, the American Adimerus. 



Fam. 43. Dermestidae. Five-segmented tarsi. Eleven-segmented, 

 clubbed antennae which can be tucked into a groove under the pronotum. 

 A smallish family of cosmopolitan beetles, many of which live on plants, 

 while others e.g. Dermestes vulpinus devour skins. Their larvae mostly 

 live on dried animal matter and Anthrenus museorum * is often very de- 

 structive in zoological Museums. They are ornamented with dense tufts 

 of hairs, and pupate in their cast larval skin. They seem capable of living 

 without water though their bodies contain as high a percentage of water 

 as other insect larvae. 



Fam. 44. Byrrhidae. Five-segmented tarsi. Legs short : the tarsi 



* A. J. Ewart, J. Linn. Soc. London (Zool.), xxx, 1907, p. 1. 



