442 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
to those of the var. coloradensis. It is in fact, merely a hairless variety 
of integroides and not a variety of integra, which is confined to the 
Eastern States and has a different kind of pubescence and a very hair- 
less male. The typical integroides, and the vars. coloradensis and 
haemorrhoidalis have exactly the same macroscopical appearance and 
differ essentially only in pilosity. They represent in the west the two 
eastern subspecies integra and obscuriventris. 
37. FE. TRUNCICOLA MUCESCENS, subsp. nov. 
Worker. Length 3.5-7 mm. 
Head large, excluding the mandibles, about as broad as long, a little 
broader behind than in front, with straight or very feebly excised pos- 
terior border and slightly convex sides. Mandibles 8-toothed. Clypeus 
strongly carinate and convex at base, its anterior border broadly 
rounded, not angular. Frontal carinae moderately diverging. An- 
tennae slender, basal funicular joints longer and more slender than 
the penultimate joints. Pro- and mesonotum not very convex, the 
mesoépinotal impression rather shallow, the epinotum with subequal 
base and declivity, the former convex, the latter feebly concave. 
Petiole rather thick and narrow, cuneate in profile, convex in front 
and behind, with rather sharp superior border, which is entire and 
somewhat angularly rounded in the middle. 
Subopaque; mandibles, clypeus, front, and sides of head more 
shining, the mandibles finely striatopunctate. Frontal area very 
smooth and shining. Gaster opaque. 
Hairs bright golden yellow, short and very sparse on the front, 
more abundant on the pro- meso- and epinotum, gula, petiolar bor- 
der, and gaster; absent on the scapes and legs. Pubescence grayish, 
very dense and rather long on the gaster, well developed but sparser 
on the head and thorax, especially on the epinotum; very sparse 
and inconspicuous on the legs. Eyes not hairy. 
Light red; mandibles, petiole, antennae, and legs darker and more 
brownish red; gaster dark or blackish brown, but appearing drab on 
account of the pubescence; anal region red. Small workers with 
the upper surface of the thorax and sometimes also the vertex, more 
brownish red. 
Femae. Length 6.5-8 mm. 
Body small. Head broader than the thorax; eyes rather small. 
Petiole much as in the worker but with blunter border. 
Mandibles, frontal area, and legs shining, remainder of body more 
opaque than in the worker. 
Erect hairs lacking on the body, except on lower surface of petiole, 
venter, and tip of gaster. There are occasionally a few hairs on the 
