SYNOPSIS OF NORTH AMERICAN SYRPHID^. 59 



third and fourth with larger quadrate spots, situated on the front part ; in 

 the female these spots, except the first pair, are smaller, and in addition, 

 on the fifth segment, there is a small, oval spot on each side in front, 

 which is scarcely apparent in the male. In the male the front femora are 

 yellowish, with more or less black toward the base, and on their poste- 

 rior part for nearly their whole length there is a row of rather long, 

 thickly set, black pile ; the tibisB yellowish, slender, suddenly and mod- 

 erately dilated at the tip; the metatarsi elongated and extraordinarily 

 dilated, produced into an acute angle on the inner distal corner ; second 

 joint a little dilated, the remaining joints not at all; the first two joints 

 wdiitish, the remainder reddish yellow. Middle femora of the male black 

 at the base, otherwise yellow ; below, near the middle, somewhat exca- 

 vated, and for a short distance with a row of short bristles ; the tibiiB 

 yellow-, on the inner side, just before the middle, suddenly narrowed, and 

 again, a little less suddenly, widened before the tip ; hind legs blackish 

 brown with yellow knees, their metatarsi thickened, especially toward 

 the base. In the female the legs are simple, only the middle tibiae 

 slightly narrowed on tiie inner side and the hind metatarsi a little thick- 

 ened ; the first two pairs of legs nearly wholly yellow, the hind pair, ex- 

 cept the base and knee, blackish brown; the spots on the abdominal seg- 

 ments are also some what smaller. Wings hyaline, stigma light yellow- 

 ish. 



Two specimens from Holland, and one male and twenty-five females 

 from the White Mountains, ISTew Hampshire (July 25-30). 



Also, several males and females from Pennsylvania (Mr. E. Keen). 



Platychirus chaetopodus, u. sp. 



Habitat. — Washington Territory !. 



$ . Length, 8™"^. Deep shining metallic green. Face thickly cov- 

 ered with yellowish dust, a small spot on the tubercle bare and shining. 

 Antennae brownish black. Frontal triangle more greenish, less thickly 

 pollinose, with black pile. Thorax and scutellum bright shining me- 

 tallic green. Abdomen opaque black, with four pairs of yellow spots ; 

 first segment shining greenish metallic ; second segment with two large 

 triangular spots, leaving the black nearly the whole width of the seg- 

 ment in front and narrowed behind, on the posterior border a rather 

 narrow black cross-band ; third and fourth segments similar, excei)t 

 that the spots are more nearly quadrilateral, the black only a little 

 widened in front, and the posterior bauds a little broader, so that in the 

 fourth segment it occupies about one-third of the width of the segment ; 

 fifth segment with two yellow spots, leaving only a posterior shining 

 greenish black triangle, extending narrowly to the front margin ; hypo- 

 X^ygium shining metallic green. Legs yellow; the middle femora with 

 a small blackish spot toward the base, hind femora and tibiae with a 

 broad black ring, hind metatarsi, except their tip and last two joints of 

 hind tarsi, black; front femora on their hind border with a row of four 



