178 Psyche [December 
gaster. Like most other Pselaphids of myrmecophilous habits, 
few are found in a single ant colony, but they are generally common, 
there being one or two in almost every nest of the host ant in the 
localities where they occur. 
Family HistErip®. 
Heterius helene sp. nov. 
Length 2mm. Color reddish-brown, in some specimens the side margins of the 
head, the margin of mandible and apex of femur piceous; shining. Form robust, 
about two-thirds as broad as long. Head above sparsely, coarsely punctate, less 
so between the eyes and beneath; clypeus about twice as broad as long, finely 
punctate; front with short yellow hairs. Thorax transverse, its breadth nearly 
twice thé length; broadest at base; front border concave, narrowly margined; sides 
straight to the constriction, which is located about five-eighths the distance from the 
anterior angle to base; median portion of disc finely, regularly punctate, with 
sparse yellow hairs; marginal portion in front of constriction very finely rugose 
longitudinally and less shining than the remainder of thorax; the anterior border 
feebly rounded, posterior portion slightly elevated; margin of sides with a rather 
dense brush of long stiff yellow hairs. Elytra at base distinctly broader than 
thorax, the width of both together about equal to length; abundantly pilose; apical 
margin punctate; marginal and humeral striz entire; third and fourth striz extend- 
ing for five-sixths the length of elytra, carinated for entire length. Propygidium 
and pygidium finely rugulose, the former with sparse long hairs. Posternum 
narrowly margined for half its length; transversely impressed at half the distance 
from end of margination to anterior border; distinctly excised at anterior border; 
margined portion shining, smooth behind and finely punctate in front. Anterior 
tibiz nearly a third as broad as long, the front margin posterior to the angle straight, 
with about eleven elongate denticles. Middle and posterior tibize one-third as 
broad as long, the outer edge rounded. 
There is considerable variation in the shade of color and a little in size. The 
hairs are rather long, curved, and moderately abundant. In some specimens they 
are almost entirely absent, probably having been scraned «#b— ** 
poy Ua auy 
wu a nave seen, except californicus and an unde- 
scribed species (hirsutus mss.) from Arizona. 
