442 bulletin: museum of comparative zoology. 



to those of the var. coloradensis. It is in fact, merely a hairless variety 

 of iniegroidcs 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. F. 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 raesonotum not very convex, the 

 mesoepinotal 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. 



Female. 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 



