wheeler: ants of the genus formica. 467 



Head, thorax, petiole, and legs dull, reddish or brownish yellow. 

 Mandibular teeth, funiculi, a blotch covering the ocellar region, a 

 large anteromedian mesonotal, and two elongate parapsidal blotches, 

 alar insertions, metanotum, and more or less of the contiguous portion 

 of the scutellum, fuscous. In some specimens the clypeus, frontal 

 region, coxae, and pleurae are infuscated. Gaster dark brown, anal 

 segment, and more or less of the base of the first gastric segment, 

 brownish yellow. Wings whitish hyaline, veins and stigma brown, 

 the latter conspicuous. 



Male. Length 5-5.5 mm. 



Mandibles slender, edentulous or indistinctly 3-toothed, pointed. 

 Maxillary palpi 5-jointed. Head rather short, broad, and convex 

 behind the eyes, narrow in the region of the cheeks. Eyes large. 

 Clypeus distinctly carinate anteriorly. Antennae slender. Thorax 

 broader than the head, rather robust, mesonotum flattened in front 

 of the scutellum. Petiole very thick, with obtuse and broadly rounded 

 border. Genitalia rather slender. 



Subopaque; frontal area, anteromedian suture of mesonotum, 

 parapsidal furrows, paraptera, and upper sui-face of gaster smooth 

 and shining. Mandibles coarsely punctate near the tips, finely stri- 

 ated toward the base. Frontal area slightly shining. 



Body and appendages clothed with microscopic grayish pubescence, 

 which is sparse and visible only in certain lights. Hairs covering the 

 body and appendages delicate, sparse, suberect, of an indistinct gray- 

 ish color. Eyes naked. 



Deep black: legs and genitalia dirty yellow; coxae, femora, tibiae, 

 and terminal tarsal joints more or less infuscated. Wings like those 

 of the female. 



Hosts (Temporary). F. fusca var. argentea and F. neogagates. 



Type locality. — Colorado: Manitou (Wheeler). 



Colorado: Florissant (Wheeler). 



The colonies of this and the following species, here included in the 

 microgyna group, are much smaller than those of the rufa group, but 

 the nests are much like those of truncicola and the allied forms, being 

 under single stones or clusters of stones, which are banked with more 

 or less vegetable detritus. 



54. F. MICROGYNA MICROGYNA var. RECiDiVA, var. nov. 



Worker. Length 3.5-6 mm. 



Differing from the worker of the typical form in lacking the erect 

 hairs on the antennal scapes and in having the hairs on the tibiae 

 shorter, more abundant, and somewhat more appressed. 



Male. Indistinguishable from the male of the typical microgyna. 

 Mandibles indistinctly toothed in two specimens. 



