1907.] Wheeler, Fungus-growing Ajits of North America. 713 



former convex in profile, the latter straight; spines long, acute and rather slender, 

 distinctly shorter than the base of the epinotum, directed obliquely upward, backward 

 and outward and continued forward as a pair of blunt, subparallel ridges on the 

 base of the epinotum. All the thoracic spines, except the inferior pronotal pair, 

 covered with small tubercles. Petiole from above oblong, slightly longer than 

 broad, abruptly narrowed anteriorly into a short peduncle; node with four 

 equidistant acute teeth. Postpetiole trapezoidal, more than twice as broad as 

 the petiole, as long as the petiole, as long as broad, semicircvdarly impressed 

 in the middle behind but with straight, entire posterior border. The border 

 of the impressed region and the sides beset with small tubercles. Gaster suboblong, 

 slightly broadest behind the middle, narrowed in front; first segment with promi- 

 nent lateral ridges and three broad longitudinal depressions on the dorsal surface. 

 Tubercles small and acute, absent in the median depression and on the ventral sur- 

 face. Legs long and like the antennal scapes covered with small tubercles. 



Mandibles with shining, coarsely punctate blades, more opaque and finely 

 striated at the base. Remainder of body and appendages opaque, granular. 



Hairs brownish, very short and curved, longer on the anterior and inferior por- 

 tions of the head and legs than on the body. Pubescence whitish, very fine and 

 dilute, confined to the antennal funicuh. 



Black; mandibles, except the teeth, thorax, petiole, and postpetiole ferruginous 

 or yellowish; pleurae more or less clouded with black or fuscous; antennae, legs and 

 apex of gaster dark brown, middle portions of femora and tibiae often blackish. 



Female. Length: 4.5-5 mm. 



Head similar to that of the worker. Pronotum with rather blunt inferior and 

 long and pointed superior spines, which are directed outward and forward and 

 slightly upward. Scutelliun convex, its posterior edge excised in the middle and 

 with a pair of acute, laterally compressed teeth. Epinotum with short convex 

 base and longer flattened declivity; spines long, slender and acute, directed back- 

 ward and somewhat outward. Petiole, postpetiole and gaster like those of the 

 worker, but the first broadest in the middle and constricted behind and the second 

 without tubercles on its upper surface. Wings 6 mm. long. 



Surface of body coarsely granular; front and vertex rugulose; mesonotum with 

 longitudinal rows of small tubercles. 



Pilosity like that of the worker, but longer on the thorax and gaster. 



Head and gaster very dark brown; thorax, pedicel, mandibles, antennae and 

 legs paler, ferruginous. Pleurae, two triangular spots on the anterior border of the 

 mesonotum, an oblong blotch on the middle of the same region behind, the parap- 

 tera and anterior comers of the scutellum, black or dark brown. Wings smoky 

 brown with darker veins and yellowish costal cell. 



Male. Length: 3.5-4.2 mm. 



Head small, without the eyes and mandibles nearly as broad as long, with 

 rounded and constricted posterior and verj'^ prominent ocellar region. Eyes large 

 and convex, their posterior orbits at the middle of the head. Mandibles acute, 

 denticulate, but rather feeble. Clypeus with straight, entire anterior border. 

 AntenniE very slender; scapes surpassing the posterior corners of the head by about 

 i their length. Pronotum with very small, acute superior spines and the inferior 

 spines reduced to angles on the lower border of the segment. Mesonotum and 

 scutellum convex, the former with distinct but shallow Mayrian furrows, the latter 



