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JOU RNAL 

OF THE 

TDpfo Dork 6fnfomoIogirflI %nmty. 

Vol. II. SEPTEMBER, 1894. No. 3. 



REVISION OF THE DIPTEROUS FAMILY 
THEREVIDjE. 

By D. W. Coquillett, Washington, D. C. 

In Osten Sacken's Catalogue of the Diptera of North America, 
four Therevid genera are credited to our fauna : Psilocephala, 
Thereva, Xestomyza and Tabuda. The genus Xestomyza, however, 
is not at present known to occur in our fauna, the single species 
heretofore referred to it (X. planiceps Loew) differing from it in so 
many important characters as to necessitate erecting a new genus 
for its reception ; the principal differences are : the much shorter 
proboscis ; the first posterior cell bisected by a crossvein, and the 
widely opened fourth posterior cell. The examination of quite a 
large series of specimens shows these characters to be constant, 
and for this new genus I would propose the name of Metaphragma. 
Our genera, including a second new one, discovered by the 
writer, may be tabulated as follows : 

1. First posterior cell entire, never bisected by a crossvein ... 2 
First posterior cell divided by a crossvein into two cells ; first antennal joint 

unusually large .... Metaphragma, gen. nov. 

2. Head nearly twice as broad as long, vertical diameter of eyes nearly twice 

their horizontal diameter . 3 

Head not as broad as long, vertical diameter of eyes equalling their horizontal 
diameter, first joint of antenna? unusually large and 
polished Nebritus, gen. nov. 

3. Face hairy 4 

Face bare Psilocephala. 

4. Third joint of antenna? at least two-thirds as long as the first . Thereva. 
Third joint of antennae one-third as long.as the unusually large 

first joint, scarcely longer than broad . . . Tabuda. 

Metaphragma, gen. nov. 

Head nearly twice as broad as long, eyes of male separated as widely as the 
two posterior ocelli; first antennal joint unusually robust, nearly as long as the 
head, nearly three times as long as the third joint, the latter only slightly wider 
than the second, destitute of bristles ; style apical, distinct, two jointed ; face very 



98 Journal New York Ent. Soc. [Vol. ii. 

oblique, greatly retreating below, pilose, especially on the sides ; proboscis quite 
slender, nearly as long as the head, labellie rather slender and as long as the pro- 
boscis proper; two subraarginal and six posterior cells, the usual first posterior cell 
being divided into two cells by a crossvein situated midway between apex of discal 
cell and the wing-margin; fourth posterior cell wide open, the anal closed; pulvilli 
present, empodium bristle-like. (Name from the Greek, meta, between, and 
fhragma, a partition. Type, Xestomyza planiceps Loew. 

Nebritus, gen. nov. 

Head depressed, slightly longer than broad, front nearly horizontal, vertical 
diameter of eyes scarcely greater than the horizontal, eyes of male separated more 
than twice as wide as the two posterior ocelli; first joint of antennte unusually 
robust, as long as the head, twice as long as the third joint, the latter scarcely as 
broad as the second; style wholly ivanting; proboscis quite slender, projecting 
nearly half the length of the head beyond the oral margin, labellre rather slender, 
as long as the proboscis proper; palpi slender, sub-clavate, slightly shorter than the 
proboscis; face bare, greatly retreating below; two submarginal and five posterior 
cells, all of them open, the anal closed; pulvilli present, the empodium bristle-like. 
(Name from the Greek, nebritos, like a fawn-skin.). Type, Nebritus pellucidus, 
sp. nov. 

Nebritus pellucidus, sp. nov. 

r$, 2 — Black, the proboscis, palpi, first antennal joint except the upperside, 
femora, tibite, base of tarsi, halteres except the extreme apex, and tip of abdomen, 
yellowish; in the female the middle of the sixth, seventh and eighth abdominal 
segments at the base are black. Front on the upper three-fourths sparse black 
pilose and opaque yellow pollinose, excepting a median line and an ocellar spot; 
lower fourth of front highly polished, sometimes yellowish below, bearing a cluster 
of black pile at base of each antenna; first antennal joint highly polished, sparsely 
beset with black pile and bristles, the third joint bearing short bristles at the base; 
face yellow pollinose except the upper edge, extending as a large spot each side, 
polished black, a similar spot on each side of the oral margin near its posterior 
edge; occiput yellow pollinose except in the center, where it is gray, a large polished 
black spot back of upper corner of each eye. Thorax opaque, somewhat bluish 
pollinose excepting four nearly equidistant yellow pollinose vittje which are beset 
with short yellow and black pile, elsewhere the sparse pile is black. Scutellum mar- 
ked with two yellow vittse beset with yellow pile; four marginal bristles. Abdomen 
opaque, lightly yellowish gray pollinose, the short pile on the basal half yellowish, 
that on the apical half largely black. Wings hyaline, the stigma yellowish. Length. 
7 to io mm. 

Southern California. Four males and two females, in April 
and June. 

Psilocephala and Thereva. — Our species have been so 
recently tabulated by the writer (Can. Ent., 1893, pages 197 — 198 
and 223 — 225) that it is quite needless to reproduce the tables in 
this place. In working up the rich material in the National 



Sept. 1894.] COQUILLETT. REVISION OF FAMILY ThEREVID/E. 99 

Museum, five undescribed species were found, which, with Dr. 
Riley's permission, are described herewith : 

Psilocephala limata, sp. nov. 

9 — Black, the tibiae, base of tarsi, and knob of halteres yellowish, narrow 
hind margins of the second and third abdominal segments, white. Front opaque, 
the upper half dark grayish-brown pollinose and black pilose, remainder of head 
white pollinose, lower half of front bare; pile of cheeks, occiput and abdomen 
(largely), white, that of the thorax and scutellum mixed black and white, 
scutellum bearing four bristles. First joint of antennae scarcely wider than the 
second, the third nearly twice as wide as and slightly longer than the first; style 
one-fifth as long as the third joint. Thorax opaque grayish-black pollinose, two 
vittse and the broad lateral margins light gray. Abdomen shining except the first 
segment, hind margins of the second, third and fourth, nearly crossing the seg- 
ments on the lateral margins, and nearly the whole of the fifth and sixth segments. 
Wings hyaline, the stigma brown; fourth posterior cell broadly open. Length, 
12 mm. 

Colorado and Washington. Two females, from Dr. Riley's 
collection. Types in National Museum. 

In my table of species referred to above this species would 
fall in with morata in couplet 4, except for the much shorter 
antennal style ; it further differs by being nearly twice as large, 
by having the thorax vittate, etc. 

Psilocephala placida, sp. nov. 

$ — Black, the antennae, proboscis, palpi, halteres, femora, tibiae, base of tarsi, 
venter and abdomen excepting the first segment and narrow bases of the three 
following ones, yellowish. First joint of antennae nearly twice as wide as the 
second, the third joint slightly wider and a trifle shorter than the first; style one- 
third as long as the third joint. Front opaque, grayish-yellow pollinose and wholly 
black pilose. Short depressed pile of thorax, scutellum and first four abdominal 
segments, yellow, the longer, erect pile and bristles black; scutellum bearing four 
bristles. Wings pale smoky-brown, center of the cells usually nearly hyaline, 
stigma dark-brown, fourth posterior cell wide open. Length, 12 mm. 

Florida. A single female from Dr. Riley's collection, now in 
the National Museum. 

In my table this species would fall in with slossoni and montivaga, 
from both of which it differs in having no black spots on the front, 
the antennae yellow, etc. 

Thereva egressus, sp. nov. 

cf— Black, the tibiae, base of tarsi, narrow hind margins of the second, third 
and fourth abdominal segments, and hypopygium (partly), yellowish. Head opaque, 
gray pollinose, pile of front and sides of face black, that in middle of face, on the 
cheeks, occiput, pleura, venter and the shorter pile of thorax, scutellum and abdo- 
men largely yellowish or whitish, the longer pile of abdomen, thorax and scutellum 



100 Journal New York Ent. Soc. [Vol. ii. 

like the bristles of the last two, black. First joint of antenna; slender, much shor- 
ter than the head, but slightly wider than the second ; third joint of nearly the 
same width and length as the first, tapering but slightly toward the apex; style one- 
sixth as long as the third joint. Thorax opaque, grayish-black pollinose, a darker 
median vitta, two vittoe and the lateral margins light gray. Abdomen opaque, 
brownish-black pollinose except the first segment and hind and lateral margins of 
the others, which are gray. Wings whitish hyaline, the stigma and a broad border 
to the veins, brown; fourth posterior cell closed. All femora provided with 
bristles. 

O — Same as the cT with these exceptions: Front near its middle marked with 
a transverse piir of transversely oval polished spots; no black pile on sides of face; 
seventh and following abdominal segments shining. Length, 10 mm. 

Colorado and California. Types in National Museum. 

This species would fall in \i\t\\ johnsoni in my table, but in the 
latter the third joint of the antennae is only three-fourths as long 
as the first, the thorax is yellowish and gray pollinose, the abdomen 
on the first six segments uniformly gray pollinose, etc. 

Thereva diversa, sp. nov. 

9 — Black, the second joint of antennre and base of the third, the palpi, 
femora, tibiae, base of tarsi, venter (largely) and broad hind margin of each abdo- 
minal segment except the first, yellowish; on the second segment this color occupies 
the last third and the lateral margins, the sixth and following segments are almost 
wholly yellowish. Head opaque, gray pollinose, a polished black spot in middle of 
front, separated from the eyes by pollen that in certain lights appears velvet-black; 
the polished spot is produced upward at its middle but is widely separated from the 
lowest ocellus; pile of front and of fourth and following abdominal segments 
largely black, that on the face, cheeks, occiput, thorax, scutellum and first three 
abdominal segments largely yellowish. First joint of antennse scarcely wider than 
the second, the third equal in width and length with the first, tapering but slightly 
toward the apex; style one-sixth as long as the third joint. Thorax opaque, gray- 
ish-black pollinose, a median, pure black vitta, also two light-gray vittse, the lateral 
margins of this same color; bristles of thorax and scutellum black. Abdomen, 
except the first segment, polished. Wings grayish-hyaline, stigma pale brown, 
veins narrowly bordered with brownish. 

rf differs from the 2 as follows : Femora, except sometimes the apex, black; 
front destitute of a polished spot; pile of face sometimes partly black; abdomen 
sub-opaque, the yellow color less extended. Length, 9 to II mm. 

Colorado, Montana and Florida. Four males and two females, 
from Dr. Riley's collection. 

There appears to be no doubt that the two sexes here described 
belong together; the Colorado examples, two males and as many 
females, each bear the same kind of a label, and are pinned lower 
down than usual, indicating that they were taken by the same 
collector. In my table, the female would fall in with flavicincta, 
in which the polished frontal spot extends to the lowest ocellus and 



Suit. 1894.] CoQUILLETT. REVISION OF FAMILY THEREVID.E. 101 

the color of the abdomen is different ; the male would fall in cou- 
plet 8, and then, in conjunction with the female, would stop at 
frontalis, which has the abdomen wholly black, or at most, with a 
very narrow yellowish hind border to some of the segments. 

Thereva nitoris, sp. nov. 

9 - Black, the tips of femora and base of tibise, reddish, balance of tibiae dark 
piceus. Front opaque, the upper two-thirds grayish-black pollinose, the remainder 
l'ght gray except a triangular velvet black spot next each eye at the junction of 
these two colors; pile on upper two-thirds of front and on proboscis black, that on 
the lowest third of front, on face, cheek, palpi and occiput, white. First joint of 
antennae scarcely wider than the second, of the same width and length as the third; 
style one-third as long as the third joint. Thorax opaque, grayish-black pollinose, 
two sub-median viltae and the broad lateral margins, light gray; the pile yellowish, 
the bristles like the four scutellar ones, black. Abdomen polished except the first 
segment, hind margins of the second, third and fifth, and a spot on each side of 
the sixth, which are whitish pollinose; pile on first three segments whitish, that 
on remainder black. Wings grayish hyaline, stigma and narrow border to the 
veins, brown; fourth posterior cell open. Length, 10 mm. 

Missouri. A single female from Dr. Riley's collection, now 
in the National Museum. 

This species would fall in with the last one in the table, mela- 
neura, a Californian species unknown to me, described from a male 
specimen ; the description by Dr. Loew, while omitting many im- 
portant characters, still indicates too many differences to permit 
us to consider this species as being identical with the one described 
above. 



A NEW ANTHRAX FROM CALIFORNIA. 

By D. W. Coquillett, Washington, D. C. 

Since the publication of my recent paper on the Bombylidae 
(Trans. Am. Ent. Soc, March, 1894), I detected a new species of 
Anthrax among some specimens submitted for names by Mr. Wm. 
Beutenmuller. The species is a very striking pne, owing to the 
bright, coppery color of the tomentum on the head and body. In 
the table of species given in the paper mentioned above (1. c, page 
97) the present species would fall in with catulina except that the 
pulvilli are wanting; it further differs from the last named species 
by the front tibiae being destitute of bristles, the brown of the 
wings filling less than one-fourth instead of nearly one-half of the 
fourth posterior cell, etc. Its description is as follows :