474 bulletin: museum of comparative zoology. 



latter flattened or slightly concave; the two surfaces passing into each 

 other through a distinct but rounded angle. Petiole narrow, in pro- 

 file compressed anteroposteriorly, with convex anterior and flattened 

 posterior surface and sharp superior border, which when seen from 

 behind is rounded and usually but slightly produced upward in the 

 middle. 



Opaque throughout, except the bases of the mandibles, the frontal 

 area, and sides of the clypeus, which are shining. Mandibles finely 

 and densely striated. Surface of, body densely and indistinctly sha- 

 greened. 



Hairs and pubescence pale yellow; the latter covering the whole 

 body and appendages, not conspicuous except on the gaster, but even 

 on this region not sufficiently 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 mandi- 

 bles are appressed and pointed, on the palpi short but numerous and 

 conspicuous. Legs and antennae naked, the former only with a series 

 of pointed bristles on the flexor surfaces of the tibiae and tarsi and a few 

 blunt hairs on the anterior surfaces of the fore coxae. 



Sordid brownish red, the smaller specimens somewhat more yellow- 

 ish red. Gaster dark brown, except a large spot at the base of the 

 first segment and the anal region, which are reddish yellow. A large 

 spot on the pronotum, one on the mesonotum, much of the postero- 

 dorsal portion of the head, the distal halves of the antennal funiculi 

 and in many specimens also the coxae and femora, dark brown or 

 blackish. These dark markings are present in the largest as well as 

 in the smallest workers. 



Host (Temporary). Probably F. fusca. 



Type locality. — Michigan: Isle Royale (H. A. Gleason). 



In coloration, this ant resembles very closely small specimens of 

 the European F. rufa i^rafensis, and can be distinguished from all the 

 preceding forms of the microgyna group by the extensive infuscation 

 of the upper surface of the head. Mr. Gleason describes the nests 

 on Isle Royale as "one of the most conspicuous features of the drier 

 tamarack swamps. They are rounded-conical in shape, 3-6 dcm. high 

 or even larger, with a diameter at the base about equalling the height. 

 They are composed within of Sphagnum, but as would be expected 

 with such material, without any definite system of galleries. The 

 outer surface is thickly covered with leaves of Cassandra, probably to 

 prevent loss of moisture by evaporation from the interior. They are 

 frequently placed near or under a bush of the Cassandra, but the same- 

 covering is used if no Cassandra is near." 



