LAND SCAVENGER-BEELES. 
63 
Family XV. ANISOTOMID^E. 
This family of minute Coleoptera is composed chiefly of the genera 
Anlsotoma- and Agatlddium, of Illiger. The first term signifies unequal 
division, and has reference probably to the structure of the antennal 
club, which, in the sub- family Anisotomides, consists of five joints, the 
second of which is the smallest. Mr. Westwood regards the second genus 
as the type of the family, which accordingly lie denominates Agathi- 
DiiDiE. But the other term is adopted by the most recent writers. 
These insects are remarkable for their very small size and their sub- 
globular bodies, those of the sub-family Agathidiides having the power 
to contract the head and thorax upon the abdomen so as to form a little 
ball. The thorax is orbicular with thiu edges, like that of the compara- 
tively gigantic Silphidae, with which, indeed, they are united as a sub- 
family by the principal modern authorities, such as Erichson, Lacor- 
daire and LeConte. 
These minute insects are found mostly in fungi and rotten wood, and 
can frequently be carught flying in the evening. 
Number of described N. A. species, thirty-five. 
Family XVI. PIIALACRIDA!. 
A small family of very small, convex, shining black insects, some- 
times two-spotted or tipt with red ; formerly confounded with the pre- 
ceding family, but separated from it by a Swedish naturalist, Paykull, 
under the generic name of Phalacrus, a word meaning bald-headed, and 
suggested probably by the rounded, shining aspect of these beetles. 
They differ from Anisotoma in having but three joints in the club of the 
antennae, and from Agatliidium in not being contractile, nor in having 
the hind margin of the thorax overlay the base of the elytra. They dif- 
fer also in their habits from the foregoing family, being usually found 
upon flowers. 
Twenty N. A. species have been described. 
Family XVII. TRICII OPTERY G I DAZ. 
This family surpasses the two former in the minuteness of its species 
—the largest not exceeding small pin-heads in size, and the smallest 
not being one-quarter as large — the species varying from about oue- 
twentietli to one-seventieth of an inch in length. Nevertheless, it is one 
of the wonders of nature that within the almost mfinitissimal compass 
of'their minute beings are contained all the divisions, the limbs and or- 
gaus of the most gigantic species. The family is founded upon the 
genus Trichopteryx, of Kirby — a term meaning hairy-winged, in reference 
to the peculiar construction of the inferior or true wings, which are com- 
