80 
Psyche 
[June 
mandibles, but minute denticles are present on those of 
costata ; frontal carinae have broad lateral lobes, but this 
condition is absent in bicolor . The humeral angles seem to 
be less sharp and projecting than in either costata or bicolor , 
and the epinotal spines are practically absent, though they 
might prove to be present on the worker when it is found. 
The sculpture is similar to that of the other two species, 
but shows the first gastric segment to have elongate and 
oval foveolae, whereas on costata they resolve themselves 
into very long grooves running the full length of the seg- 
ment, and in bicolor the sculpturing on this segment is al- 
most completely absent, leaving the surface smooth and 
shining. The ventral blade on the petiole is rounded while in 
costata its apical edge is notched, and a midventral keel or 
ridge is present on the postpetioje of posteropsis , this struc- 
ture being absent on the other species. The comparisons 
made are between a female and the worker caste of the 
other species, but the differences are sufficiently striking 
to support the description of a new form. In addition, there 
are important differences in size; posteropsis ($), is 
slightly over 5 mm. in length, costata ( ? ) , is over 8mm., 
and bicolor ( ? ) , is over 5 mm. Although these ants are 
ponerines, undoubtedly, the worker of posteropsis, if known, 
would prove to be considerably less than 5 mm. long. 
Camponotus (Myrmostenus) cooperi n. sp. 
Female. Length, 6.25 mm., cephalic index, .55 
Head, excluding the mandibles elongate, as indicated by 
the head index; rectangular in general shape, the widest 
point at the anterior angles where the mandibles articulate. 
Occipital angles abrupt, and posterior margin straight. 
Sides of head slightly concave, with the eyes medium sized 
and almost flat, located midway between the anterior and 
posterior ends. Ocelli about midway between the eyes and 
posterior border of the head. Clypeus convex, and produced 
anteriorly into a cone-like process. Frontal carinae low and 
indistinct, leaving the antennal insertions exposed. Anten- 
nae 10-segmented, scapes short, extending posteriorly only 
as far as the eyes; narrow at the base and expanding 
abruptly toward the apex. Funiculi gradually increasing 
