112 . NORTH AMERICAN TIPULIDAE 



58. Antennae thir teen-jointed 59 



Antennae with more than thirteen joints in both sexes. . . polymera Loew 



59. Lateral stripe and posterior margin of abdominal segments, black. 



approximate spec. n. 

 Abdomen with lateral and ventral rows of black spots 60 



60. Segments of antennal flagellum excised beneath; abdomen with dorsal 



row of spots; eighth sternite with deep, u-shaped emargination. 



brevicornis Doane 



Segments of flagellum cylindroidal ; abdomen with dorsal vitta; eighth 



sternite protuberant, scarcely emarginate stigmatica spec. n. 



Pachyrhina oslari spec. n. (PL IV, fig. 1., pi. V, fig. 21.) 



Tipuloid; entirely black with a grayish-white pruinosity. Flagellar joints 

 of the antennae prolonged beneath at the apex, giving the antennae a serrate 

 appearance. Stigma pale brown. 



Male. Length, 11.5 mm.; wing, 12.5 mm. 



Head. Face, space about base of antennae, antero-inferior periorbital mar- 

 gin and sides of occiput, densely white pruinose, median space of occiput dull 

 black. Proboscis very short and thick, frontal prolongation beset with black 

 hairs. Antennae robust, short, entirely black, without whorls of setaceous 

 hairs, with a very short, white pubescence on the apical margin of the seg- 

 ments, the apices of segments three to seven extended beneath, less marked in 

 the following segments, joints eleven and twelve longer than the preceding 

 ones, the last joint very slender. 



Thorax. Pronotal scutellum sordid yellow; scutum hairy, darker in middle 

 portion. Mesonotal praescutum without hairy vestiture, grayish-pruinose, 

 stripes blackish, broad, the median stripe divided by a dark line, the lateral 

 stripes indistinctly prolonged upon the mesonotal scutum. Scutellum and 

 postnotum grayish-white pruinose with dark median line. Pleura, with the 

 exception of the upper part of the mesopleural sclerite, densely grayish- 

 white pruinose; pleuro-dorsal membrane dark yellowish-brown. 



Legs rather robust, of moderate length, brown; coxae densely grayish-white 

 pruinose, femora yellowish-brown, darker towards the apices, pubescence very 

 short, black, appressed; tarsi black. Halteres dark brown, yellowish at base. 

 Wings grayish, broad; Cells C and Sc yellowish, stigma pale yellowish- 

 brown; vein R setulose, vein Sc 1 atrophied; venation as in figure. 



Abdomen grayish-pruinose except along the dorsum, where its absence leaves 

 a broad, black stripe of the ground color; the extreme posterior margin of 

 segments three to eight, whitish, the lateral margins more broadly, yellowish- 

 white. Eighth sternite with a slight emargination in the middle and one on 

 each side. Hypopygium blackish, appendages ferruginous; ninth tergite very 

 short, impressed anteriorly, posterior margin emarginate in the middle, lateral 

 angles acute, upper appendages broadly lanceolate, inflexed; ninth sternite 

 with closed suture; pleural suture absent. PI. V, fig. 21. 



Female. Length, 13 mm.; wing, 12 mm. 



Very similar to the male. Antennae shorter and less markedly denticulate. 

 Sides of scutellum and postnotum yellowish. The lateral margin of the ab- 

 dominal tergites scarcely at all paler. Ovipositor ferruginous, dorsal valves 



