1939] 
A New Subspecies of Crematog aster 
139 
tudinal rugae in the typical minutissima are well developed 
and at least two of them lie well in towards the center of the 
pronotum. In missouriensis the rugae are variable in posi- 
tion but when they occur at the edge of the thorax, as fre- 
quently happens, they are more prominent than in thoracica. 
The shape of the petiole seen from above is usually quite 
characteristic in thoracica. The sides gently diverge behind 
so that the petiole is widest at the rear. The difference is not 
great but the wedge-like appearance is rather different from 
that of the other two subspecies, where the petiole is more 
quadrate with the sides subparallel and widest, if there is 
much difference in width, at the middle. The epinotal spines 
of thoracica are short like those of the typical form. In other 
respects thoracica is very similar to the typical minutissima. 
Described from a series of workers taken by W. M. Mann 
in Miller Canyon, Huachuca Mountains, Arizona (elevation 
6000 ft.). In addition to this type series I have seen other 
specimens also secured by Dr. Mann, in Ramsey Canyon 
(elevation 5800 ft.) in the Huachucas. 
Holotype (worker) and a series of paratypes in the col- 
lection of the Museum of Comparative Zoology. Additional 
paratypes in the collection of the American Museum of 
Natural History and the collection of the writer. 
The three subspecies of minutissima and our single re- 
maining species in the subgenus Orthocrema, Cr. (O.) ari- 
zonensis, may be separated as follows : 
1. Tip of the antennal scape in repose notably surpassing 
the occipital border ; color yellow ; the gaster clothed 
with abundant long hairs 2 
Tip of the antennal scape in repose failing to reach the 
occipital border ; color piceous brown ; the erect hairs 
of the gaster short and sparse : arizonensis 
2. Dorsum of the promesonotum very smooth and shin- 
ing ; rugae, if present, feeble and confined to the edge 
of the pronotum : minutissima thoracica 
Dorsum of the promesonotum finely punctate in addi- 
tion to the longitudinal rugae, the surface feebly shin- 
ing; rugae well-developed and often placed towards 
the center of the thorax 3 
