326 MICHIGAN SURVEY, 1908. 



americanus is small, like neoniger, but brown and has few erect hairs 

 on the body and none on the legs and scapes. It is closely related to 

 the palearctic variety nlienus Forster, and like this form inhabits warm 

 and rather dry localities. It is the common form of niger throughout 

 the Xortliern States. L. sitlcucnsis occurs in Alaska, Nova Scotia and in 

 the damp alpine meadows of the Kocky Mountains at altitudes between 

 8000 and 9000 ft. L. neonif/cr occurs in dryer situations at somewhat 

 lo'wer elevations and is occasionally found even near sea-level in isolated 

 colonies in our northern woods. Varieties (hybrids?) Intermediate be- 

 tween neoniger and americanus also occur in these same localities. 



5. Formica sanguinca aficrva Forel. Workers from two colonies: 78 

 (I, 2), 72 (I, 2) H. A. G. "This is one of the commonest species on the 

 rock ridges, but constructs its nest either in or under decaying wood. 

 On the ridge north of the light house, a nest (72) was made under a 

 rather small rotten stick, and the soil beneath was composed mainly of 

 finely comminuted fragments of the wood. The second colony (7S) had 

 constructed a nest in the interior of a large decaying log." (Gleason). 

 This subspecies has been taken hitherto only at Toronto (Forel), on the 

 summit of Mt. Washington (Mrs. A. T. Slosson), among the Litchfield 

 Hills of Connecticut (Wheeler) and in Casco Bay, Maine (Wheeler). 

 It is a decidedly boreal form, approaching the typical palearctic 

 sanguinca. in size and coloration. There were no slaves accompanying 

 the specimens from Isle Royale, a fact which tends to confirm the con- 

 clusions of Forel and myself that this subspecies usually lives in pure 

 colonies. 



6. Formica adamsi sp. nov. Worker. Length 3.5-5mm. Allied to 

 F. rufa L. Head, including the mandibles, nearly as broad as long 

 even in the smallest individuals, with straight posterior border, rounded 

 posterior corners, and slightly but distinctly convex sides. Eyes large. 

 Mandibles 7-8 toothed. Clypeus prominently carinate, with broadly 

 rounded anterior border, not produced in the middle. Palpi of moderate 

 length. Antennae slender, scapes nearly straight at the base, funicular 

 joints all distinctly longer than broad, the basal somewhat more slender 

 and longer than the apical joints. Pro- and mesonotum moderately 

 rounded, convex, the latter eliptical and nearly twice as long as broad, 

 the former a little broader than long. Epinotum with subequal base 

 and declivity, the former slightly convex, the latter flattened or slightly 

 concave; the two surfaces in profile passing into each other through a 

 rounded angle. Petiole more than half as broad as the epinotum, in 

 profile with convex anterior and flattened posterior surface and sharp 

 upper border; seen from behind the border is' rounded and but feebly 

 or not at all produced upward in the middle. Gaster and legs of the 

 usual shape. 



Opaque throughout; only the mandibles, frontal area and sides of the 

 clypeus faintly shining or glossy. Mandibles finely and densely striated. 

 Surface of body densely and indistinctly shagreened. 



Hairs and pubescens pale yellow; the latter covering the whole body 

 and appendages, not conspicuous except on the gastei', but even on 

 this region not sufflciently dense to conceal the surface sculpture. Hairs 

 short, sparse and obtuse, in several rows on the gastric segments; on 

 the thorax confined to the upper portions of the pro- and mesonotum, 

 on the head to the clypeus, front and vertex. The hairs on the mandibles 



