106 
Psyche 
[June-Sept. 
tangled roots of the grass, while the other 2 were in the soil 
2 to 8 cm. below the surface. Galleries of Camponotus cas- 
taneus subsp. americanus Mayr ran close to one nest, but 
we were unable to find any connection between the two. 
Two colonies were found in the cedar thicket described 
above under S. missouriensis. One of these was nesting in 
an opening at the bottom of the humus, the other in a small 
cavity at the base of an old rotted cedar stump. Stray 
workers in these and other places were often found by pull- 
ing back the top cover of the humus in places where spring- 
tails were abundant. 
Strumigenys (Cephaloxys) abdita, sp. n. 
Worker: (PI. 3, fig. 6 ) : Length, 2 mm. 
Head, exclusive of mandibles, 1.3 times as long as the 
greatest width across the occipital lobes, 2.4 times as long 
as the greatest width of the clypeus ; sides of anterior por- 
tion of head very slightly convergent; clypeus short and 
broad, the anterior border strongly flattened or truncate but 
not so as to make the head appear .sharply rectangular ; man- 
dibles rather long and slender, compressed dorso-ventrally, 
- I /5 the length of the head alone, the internal border 
nearly straight, the external border straight on the basal 
half, gently convex on the apical half ; mandibles with a pair 
of large basal teeth partially concealed by the clyeus when 
the mandibles are closed ; basal teeth followed by a toothless 
space Yg the length of the portion of the mandibles anterior 
to them ; terminal teeth comprising a compact row of 4 or 5 
pair of large acute teeth, the second largest, the rest decreas- 
ing somewhat in length anteriorly, meeting and merging 
with little interruption into the apical series of a number of 
small teeth on the deflected tip of the mandibles; antennal 
scapes slightly angulate basally; first joint as long as the 
fourth; terminal joint 1 % times as long as the rest of the 
funiculus. Humeri prominent, broadly angulate; median 
dorsal carina of thorax obsolescent ; prominent lateral 
carinae present on base of epinotum terminating in the 
epinotal spines ; epinotal spines somewhat longer than broad 
at the base, acute, flattened ; infraspinal lamellae moderately 
wide dorsally, each suddenly expanding ventrally into a wide, 
