THE AUSTRALIAN NATURALIST. 39 
having the elytra entirely covering the abdomen and the tarsi 
five jointed; the antennae thickened or clubbed at the tips. 
These insects are similar in colouring to the Pselaphidae, but 
are usually smaller and the elytra more shiny.” ‘Lhe largest 
species of this family taken by me does not exceed 1.5 mm. 
Staphylinidae, of various shades of red, brown or black are 
often found in numbers running actively about the nests. Most 
species are shiny, and do not exceed 4 mm. in length. The 
commonest Sydney species being only 1.5 mm. 
The family Vrichopterygidae which contains some of the 
smallest beetles in the world are represented in the ants’ nests 
by the genus Rodwayia. In this genus the eyes are not present. 
Notwithstanding this they can run most actively about the nests. 
They are brown in colour, ranging from 0.5 to 1 mm. in length, 
and closely resembling some species of mites found in ants’ 
nests. 
Lhe Histeridae are perhaps among the most difficult to col- 
lect in the nests owing to their remaining motionless for long 
periods when disturbed, and in many cases being covered with 
dust. In the genera Chlamydopsis, Ectatommiphila and others, 
the head can be completely withdrawn into the thorax; the an- 
tennae folding into hollows on each side of the head, so that 
when viewed from the front it presents an almost flat surface. 
The tarsi fold up into hollows in the tibiae; the legs are then 
closely adpressed to the body, giving the whole beetle the ap- 
pearance of a small piece of debris. There is a species to be 
taken in the Sydney district which can, however, be easily seen 
when in the nests, its colour being a light reddish yellow. This 
is Chlamydopsis epipleuralis, a species which quickly makes off 
as soon as disturbed. Length 2.75 mm. 
There are two species of Colydiidae frequently found, Nep- 
haris costata and Kershawia rugiceps. Both are dull brown 
beetles, the former 3 mm. the latter 4 mm. in length. 
Ptinidae are represented by a number of remarkable forms 
having the antennae variable, both in the number of joints and 
in shape. In colour they vary from black to various shades of 
brown, and in length from about 4 to 1 mm. or less. 
Chlamydopsis epipleuralis was figured hy me in the “Aus- 
tralian Naturalist,” Vol. IV., pt. 2; pl. IL., pp. 20 and 53. 
Four species of different. genera of the family Péinidae 
and the genus Huclarkia of the family Colydiidae will be found 
figured in the “Australian Zoologist,” Vol. I., pt. 8; pl. XIX, 
p. 245. 
