wheeler: ants of the genus formica. 493 



Worker. 4-6.3 mm. 



Closely related to F. cxsecta. Head proportionally broader, with 

 less deeply excised posterior border and more romided posterior corners, 

 the cheeks rather convex, front depressed. Mandibles S-toothed, 

 with 2 or 3 minute additional teeth on the basal border. Clypeus 

 indistinctly carinate, its anterior portion flattened and its border 

 slightly reflected. Frontal area triangular, a little longer than broad. 

 Maxillary palpi long, 6-jointed. Epinotum in profile not so rounded 

 as in e.rsccta, distinctly angular, with distinct base and declivity, the 

 former horizontal, very feebly convex, the latter very sloping. Petiole 

 very much like that of exsecta, its margin sharp and deeply excised. 



Head and gaster rather smooth and shining, finely shagreened. 

 Frontal area smooth and shining. 



Pilosity and pubescence very feebly developed, only the clypeus, 

 mouthparts, venter, and tip of gaster with sparse hairs. 



Head, thorax, and petiole ferruginous; front, vertex, and posterior 

 portion of head, especially in small workers, often darker; antennal 

 funiculi, anterior border of clypeus, dental border of mandibles, some- 

 times also the legs in part, brown; gaster blackish brown. 



Female. Length 5-6.3 mm. 



Very small. Resembling the worker in the structure of the head; 

 the thorax and petiole as in F. exsecta. 



Body very shining, especially the head, thoracic dorsum, and gaster. 



Pilosity and pubescence as in the worker. 



Upper surface of head, posterior border of pronotum, mesonotum, 

 scutellum, and border of petiole and gaster, except the anal region, 

 blackish brown. Remainder of body darker or lighter yellowish or 

 reddish brown. Wings very pale grayish hyaline, with pale brown 

 veins and darker stigma. 



Male. Length 6-6.5 mm. 



More slender than the male exsecta; posterior border of head broadly 

 excised but sometimes indistinctly so. Mandibles broad, pointed, 

 edentulous. Palpi as in the worker. Petiole low and thick, as broad 

 as high, truncated above, with blunt, entire border. 



More shining than the male of exsecta, especially the gaster. 

 Frontal area and mandibles more shining than the remainder of the 

 head. 



Hairs and pubescence no more abundant than in the worker and 

 female, even sparser on the gaster. Mesonotum with a few short, 

 erect hairs. Eyes hairless. 



Black; genitalia and legs yellowish, middle portions of femora and 

 tibiae more or less infuscated. Wings pale grayish hyaline as in the 

 female. 



Sweden: Alno Island, in the Gulf of Bothnia, near Sundsvall. 

 This form is regarded by Emery as an extreme race of F. exsecta, 



