ECOLOGY OP ISLE ROYALE. 327 



are appressed and pointed, on the palpi short but numerous and conspic- 

 uous. Legs naked except for 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 brownivsh red, the smaller specimens somewhat more yellowish 

 red. Gaster dark brown, except a large spot on the base of the first seg- 

 ment and the anal region, which are reddish yellow. A large spot on 

 the pronotum, one on the mesonotum, much of the posterior portion of 

 the head, the distal halves of the antennal funiculi and in many speci- 

 mens also the coxae and femora, dark brown or blackish. These dark 

 markings are present in the largest as well as in the smallest workers. 

 Teeth of mandibles black. 



Described from numerous specimens taken from a single colony: 115 

 (], 6) H. A. G. A dozen workers taken by myself on Pikes Peak, Col- 

 orado, near timber line, at an altitude of 10,500 to 11,000 ft. differ from 

 the Isle Royale specimens only in having the frontal area smooth and 

 shining, in having the middle of the petiolar border produced upward 

 as a distinct, blunt point, and in the less extensive infuscation of the 

 head, pro- and mesonotum. These specimens may be regarded as repre- 

 senting a distinct variety, nlpitm var. nov. Both this and the typical 

 adainsi may be distinguished from our other North American forms of 

 ■the rufa group by their small size, opaque surface and peculiar color- 

 ing and pilosity. The following collector's note on the Isle Royale 

 specimens adds some ethological characters which are not seen in the 

 other small forms of the rufa group known to me: "The nests of this 

 ant are one of the most conspicuous features of the drier tamarack 

 xwamps. They arc rounded-conical in shape, .3 6 dcm. high or even 

 larger and 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 oiiter 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." (H. A. Gleason). 



7. Formica rufa o'hscuriventris Mavr. Workers from six colonies : 

 46 (I, 1), 47 (I, 1), 63 (I, 2), 76 (I, 2), 114 (I, 6), 14 (112) H. A. G. 

 "This subspecies occurs on the rock beaches (I, 1, 46, 47) where it 

 forages about on the surface and in crevices but is more abundant on 

 the jack pine ridges (I, 5, 63) and on the rock clearings (I, 2, 76)." 



I recently described this subspecies as F. dryas, but an examination 

 during the past summer of some of Mayr's types in Professor Forel's 

 collection, shows that in so doing I created a synonym. Mayr's original 

 description based on specimens from Connnecticut is entirely inade- 

 quate, and the list of localities which he later cited for o'hscuriventris 

 shows that he lumped together a number of different forms belonging 

 to the rufa group The name oiscuriventris, therefore, should be re- 

 stricted to the form having the characters of my F. dryas. This ant is 

 rare in the Eastern and Northern States and evidently belongs to the 

 boreal fauna. 



8. Formica fusca L. var. suhsericea Sav. Workers from 11 colonies: 

 23 (I, 5), 102 (V. 2), 131 (V, 2), C. C. 'a., and 80 (I, 5), 81 (I, 5), 

 100 (I, 5), 102 (I, 5), 223 (V, 3), 224 (V, 3), 226 (V, 3), 227 (V, 3) 



