Notes and Descriptions of Syrphidae.
BY W. A. SNOW.
WITHPLATE VII.
Among the insects obtained by Prof. F. H. Snow in a recent trip to Colorado, is an excellent representative collection of the Diptera. The material for the following notes on Syrphidae is chiefly drawn from this collection. That such a collection affords so many points of interest in this, one of the best studied families of North American Diptera, is an evidence of the rich field that is presented by this important and little-studied order of insects.
CalliceraPanzer, Fauna Germanica, 1806.
Callicerais a small genus hitherto supposed to be peculiar to Europe. The species are found in the high mountains, where the males are often taken while hovering in the air. The present collection includes numerous specimens of a species taken near the summit of Mt. Deception, in Manitou Park, Colorado, at an altitude of nine thousand feet.
The occurrence of members of this genus in the western part of the United States is a fact of especial interest and further substantiates the rule that American forms common to Europe are more apt to occur in the western regions.Arctophila flagransOsten Sacken, is a case precisely similar to the present one, belonging as it does to a small European genus of mountain flies, and described from Colorado.
As the genus is a new one to our fauna, I here give an amended transcription of the generic characters from Schiner’s Fauna Austriaca, to include the new species, which differs only in unimportant details.
Rather large, stout, green or black species with metallic lustre and abundant, long pile. Head hemispherical, somewhat broader than the thorax. Antennae porrect, longer than the head, somewhat remote at their base, inserted upon a protuberance of the front; first joint sometimes elongate; second joint shorter than, or as long as, the first joint; third joint one to three times the length of the first two joints taken together, with a short, terminal style. Face broad, underthe antennae concave in profile; an obtuse tubercle below the middle; on the sides thickly covered with pile. Proboscis rather prominent, with broad labella. Eyes hairy, holoptic in the male. Abdomen elliptical, as long or longer than the thorax. Legs moderately strong. Third longitudinal vein straight, first posterior cell distally short petiolate; marginal cell open; cross-vein situated near the middle of the discal cell, oblique.
Plate vii, f. 4.
Male.Black, densely golden red pilose. Frontal triangle, face and cheeks deep black, shining, covered thickly with black pile, save a median facial stripe. Antennae black, basal third of third joint on the under side red; first joint short; second joint not more than half as long as the first; third joint three times as long as the first and second joints taken together; gradually broadened for a third of its length, and then attenuated; style white. Eyes thickly clothed with golden pile. Thorax and abdomen covered everywhere with long golden red pile. Legs black; tarsal joints below and at their articulations reddish. Wings nearly hyaline, brownish on the anterior basal portion; stigma yellow.
Length 11 millimeters. Three specimens, Colorado.
The genus may be distinguished fromPelecocera, in Williston’s dichotomic table of the genera of North American Syrphidae, by the pilose eyes.
Plate vii, f. 1.
Male.Large, yellowish pilose species, in shape globose. Antennae reddish black, the first joint about as long as the following two together; second joint not one-third as long as the third. Face dark metallic green, shining, thickly covered with golden yellow pile. Front black, with similar pile, narrowed in the middle. Eyes bare. Thorax and scutellum deep metallic green, with long, thick, golden pile; scutellum gently emarginate, the small obtuse tubercles approximate. Abdomen short and broad, black, moderately shining; first two segments and the hypopygium somewhat green; pile at base yellow, elsewhere short, black. Legs black, with black pile; front tibiae and their metatarsi, on the inner side, with short golden pile; hind metatarsi incrassate and longer than the three following joints taken together. Wings uniformly subinfuscate; veins at the outer part of the first posterior and discal cells sinuous and rounded.
Length 12 millimeters. One specimen.
Eight specimens from Colorado, which vary not a little from each other and from Williston’s description. They seem to belong here, however, better than elsewhere. In one specimen, the second joint of the antennae is shorter than the first, and only one-fourth the length of the third. In five examples the second abdominal cross-band is not interrupted; in the others it is distinctly parted. In two, the third band does not reach the yellow of the broad hind margin; in two others it barely touches it; in five, the two bands broadly coalesce. The yellow of the fifth segment, in four specimens, incloses a black, inverted V; in two others an inverted Y.
Three specimens, Colorado. These may be located under Schiner’s varietytaeniatus.
Eleven specimens, Colorado, which answer well to the descriptions. The metallic band of the fourth abdominal segment is sometimes interrupted, and there is usually a triangular opaque black spot near the anterior border of the fifth segment. “The female, hitherto unknown, has the front broad above, pollinose, except on the upper part, and with black pile; the thorax more shining metallic blue; the tibiae yellow, and on the third and fourth abdominal segments there is a narrow shining stripe, bisecting the black, as in the fourth segment of the male. The male has some long black hairs on the outer side of the front and middle tibiae, which are inconspicuous in the female. It is evident, from the lighter color of the tibiae, that Say’s specimens were females.†Williston, l. c.
A single female specimen from Manitou Park.
Male.Face and front dark metallic blue, shining, thinly covered with light-colored pollen; tubercle and epistoma black, shining, the former small. Antennae black, third joint yellowish red below, oblong. Pile of frontal and vertical triangles dusky. Thorax bronze-black, shining, sometimes bluish black, the pubescence white. Halteres yellowish. Abdomen long and narrow, with almost parallel sides; first segment metallic blue, shining; second segment opaque, or subopaque, black, with a light metallescent scallop on the sides, reaching to the distal third of the segment; third and fourth segments similar, marked anteriorly by a wide, interrupted, or subinterrupted blue fascia, deeply and widely emarginated, or concave behind; hind border of the third, and sometimes of the second segment, narrowly brown; fifth segment and the hypopygium metallic bluish green; sidesof the abdomen with silvery white pile, longest and thickest at the base; the blue marking are whitish pruinose. Femora, except the tip, a broad ring on the tibiae, and the four posterior tarsi, black; elsewhere brownish or yellowish. Wings hyaline, stigma yellowish.
Length 7-8 millimeters.
Numerous specimens, Colorado.
Four specimens, Colorado. These specimens vary not a little from each other, and somewhat from the descriptions. One female is very small, not over seven millimeters in length, and with the spots on the third and fourth abdominal segments hardly oblique. One male has the hind femora black as far as the tip, while in three females the black does not extend beyond the middle.
A single female specimen, from Colorado, agrees well with the description drawn from males. The pile of the thorax is more whitish than orange-yellow, and there are light colored lateral margins on the anterior part of the thorax.
Plate vii, f. 3.
Male.Eyes bare. Face greenish yellow on the sides, yellow in the middle; a rather broad black line marks the border of the mouth and is lost in the black of the cheeks. Frontal triangle yellow, with long black pile. Antennae dark brown, more or less reddish below. Pile of occiput light yellow. Dorsum of thorax deep metallic green, the scutellum olivaceous yellow; both with light yellow pile. First segment of the abdomen shining black; second segment opaque black, with the lateral margins and hind border shining, and with a broad, yellow, interrupted band, not reaching the lateral margins; third segment similar, but with the yellow band somewhat wider, interrupted or subinterrupted and slightly bilaterally oblique; fourth and fifth segments orange-red, the sides narrowly black; the fourth segment shows indistinctly a broad interrupted band of a somewhat lighter color, corresponding to the yellow bands of the preceding segments. Legs light brown; basal third of the front and middle femora and basal half of the hind femora black. Wings hyaline, stigma yellowish.
Female.Head wanting. Thorax purplish brown. The yellow band on the second abdominal segment narrower, the second band straight, narrower and interrupted. Legs light brown, except the proximal end of the femora, which is black.
Length 9 millimeters. Three males and one female, Colorado.
Two specimens from Colorado undoubtedly come here. The species was described from a single male specimen. A female specimen offers the following differences or additions: Length nine millimeters, mesonotum more greenish black or bronze, the pile obscure whitish; fifth abdominal segment without yellow spots on the anterior angles; legs yellow, with the basal half of the front and middle femora, the hind femora except the tip, a broad band on the hind tibiae, and the hind tarsi, black.
Five specimens, Colorado.
Numerous specimens, Colorado.
Five female specimens, Colorado. The only western locality heretofore given is Arizona (Williston).
Five specimens, Colorado.
Numerous specimens from Colorado, showing very great variation.
Sphaerophoria cylindricaSay.
Twenty specimens, Colorado. I think the specimens belong here, though a positive identification is hardly possible at present.
One specimen, Colorado. This is the first time that this species has been recorded from beyond the Mississippi.
Two specimens, Colorado, representing the extremes of variation in the species. The male corresponds toC. lentumWilliston. Specimens of this species were bred fromOpuntia missouriensis, in company with others ofVolucella fasciataMacq.
Sixteen specimens from Minnesota and Colorado vary in the markings of the second abdominal segment, and in the color of the legs. Some have no spots at all on the second segment; in others the two yellow dots are conspicuous, approaching, in size and shape, the markings of the third segment. The tibiae vary from light yellow to reddish brown.
Plate vii, f. 2.
Head light yellowish brown, largely concealed beneath light glistening pollen; the shining ground color shows just above the antennae and in a stripe on the cheeks, extending from the eye to the mouth opening. Antennae wanting. Dorsum of thorax brown, covered with grayish pollen; anteriorly with two approximated, linear, blackish stripes; laterally with a broad, interrupted stripe. Scutellum light brown, with yellowish pollen. Abdomen but little longer than broad; yellowish gray pollinose; second segment with a circular brown spot in the anterior corners; the two following segments are marked with corresponding elliptical spots, and, in the middle of the anterior border with a triangular spot; on the fifth segment are two small round spots. Legs uniformly reddish brown, with light colored pollen and short whitish pile. Wing hyaline, distinctly clouded at anterior cross-vein, on the veins at the anterior outer corner of the discal cell and on the ultimate section of the fourth vein; posterior cross-vein about as long as the penultimate section of the fourth vein, the included angle obtuse.
Length 5 millimeters. One specimen, Colorado.
Numerous specimens, Colorado. The commonest Syrphid of the mountain meadows. Some specimens have very indistinct brownish spots on the second abdominal segment, and, when this is the case, the middle of the wing generally shows a brown spot, and brown clouds along the anterior veins between the spot and the base of the wing.
One male specimen, Colorado.
Numerous specimens, Colorado.
Eight specimens, Colorado. The glistening pile of the face and front varies from white to a golden yellow. On the dorsum of the thorax purplish stripes are distinctly visible. The fourth segment of the male abdomen is often red, as in the female abdomen.
Eight specimens, Colorado.
A single, male specimen, collected by Mr. W. J. Coleman, at Lawrence, and agreeing exactly with the description. The only other known specimen of this species is the type, at Washington, from Connecticut.
Seven specimens, Lawrence, Kansas, (F. H. Snow and E. S. Tucker). The species has not hitherto been recorded west of New York.