114 
BRITISH BEETLES. 
thoracic spiracles hidden ; the thorax entirely horny 
below ; the anterior coxa; globose, not prominent, and 
the posterior transverse ; the tarsi five-jointed (in our 
species) ; and the apical segment of the abdomen 
inconspicuous. 
P. quadricornis (Plate V., Fig. 5) is found under 
bark, sometimes in considerable numbers; it is elongate, 
flat, and narrow, pitchy-black and shining, with the 
elytra, antennae, legs, and apex of abdomen reddish. 
In the male the head is much enlarged, the forehead 
hollowed, with a horn on each side stretching forwards, 
and the mandibles also armed each with another horn, 
larger than itself. 
Occasionally specimens of the male occur in which 
these characters are developed to an inordinate extent. 
Lastly, if we leave them in this position, the Micro- 
peplinje, also represented by a single genus, have the 
spiracles hidden and thorax horny, as in the last 
family; the anterior coxae not prominent, and the 
posterior globose ; the front and hind legs distant at 
the base; the tarsi three-jointed; and the antennae 
nine-jointed, knobbed, and fitting into grooves. 
Their sculpture is very remarkable, the entire upper 
surface being strongly costated or divided by longitu- 
dinal ridges; on account of which, added to their 
knobbed antennae and short compact form, they have 
often been classed among the Nitidulidse, somewhat 
resembling also certain species of Onthophilus. 
Micropeplus margaritx (Plate V ., Fig’. 0), found — like 
its congeners — in vegetable refuse, is not uncommon; 
and M. tesserula, the rarest species, may be known by 
its polished appearance. 
