The Bremus Resembling Mallophorae of the Southeastern United States.
Psyche 32(3):190-194, 1925.
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190 Psyche [June
THE BREMUS RESEMBLING MALLOPHORZ OF THE
SOUTHEASTERN UNITED STATES (DIPTERA
BY S. W. BROMLEY,
The robber-flies of the genus Mallophora are, for the most part, rather large and densely-pilose, and are of a more compact build than most of the other members of the Asilidse. Nearly all of them resemble bees of one kind or another, and the species of the particular section of this genus here treated bear a marked resemblance to bumble-bees. In some cases the resemblance is actually specific. For example, Mallophora orcina (Wied.) is a counterpart of the worker of the bumble-bee, Bremus pennsyl- vanicus. The resemblance is, of course, most striking in the field, particularly if the flight of the asilid is directed away from the observer. The illusion is destroyed, however, when the flight of the insect is directed toward the observer, as the cons- picuous yellow beard and mystax of the fly dispel all doubts as to its identity. When the robber-fly is at rest, moreover, the posture assumed is entirely different from that of any bumble- bee. In fact, it seems to the writer that the mimicry is not nearly as striking as in the case of some of the robber-flies of the genus Dasyllis, such as D. thoracica, where the imitation of a bumble-bee is so exact that even an experienced collector may be mislead when the insect is in flight. Of the species here considered, M. ordna is the most abun- dant and has the widest geographical distribution. I have taken this species commonly in Northwestern Missouri, and have examined specimens from most of the southern states, including Florida and Texas. It is found in southern Ohio and, according to Mr. C. T. Greene of the National Museum, is very common in the neighborhood of Washington, D. C. The type-locality of Wiedeman's specimen is "Savannah." In Arizona, a very closely related species, MaZlophora fulva Banks (Canadian En- tomologist vol. 43, no. 4, 1911, p. 130), has been taken. This is so close to orcina that it may possibly prove to be a western variety. However, until a full series showing the merging of the
19251 Bremus Resembling Mallophorce of Southeastern U. S. 191 characters is available, it is best to consider it a distinct species. Mallophora faiitrix 0. S. another western species, smaller than, but bearing a superficial resemblance to, orcina, may be easily distinguished by the reddish ground color of the femora (instead of black) and the absence of black pile on the abdomen. Mallophora bomboides (Wied.) is abundant in some parts of Florida and has also been taken in Georgia. The type locality is "Georgia." The only records of M. nigra Willst. that I could obtain are from Florida. M. rex sp. n. I have from N. Carolina, Mississippi, and Florida; while M. chrysomela sp. n. is rep- resented by specimens from Georgia and Mississippi. All five species are quite closely related. The first species to be described was named bomboides by Wiedernan evidently because of its resemblance to a bumble-bee. The resemblance is not as striking, however, when the insect is observed in the field, as in the case of orcina.
In 1893, Coquillet devised a key to the genus Mallophora dealing with all species then known to occur in America north of Mexico (Canadian Entomologist, vol. 25, no. 5, p. 118). The key presented below does not include all of the species of this gcnus, but simply a natural group of five species occurring in the southeastern United States, and is included for the purpose of bringing out clearly the differences existing between the two new species described and those most nearly resembling them. 1.
Pile of abdomen wholly black. ............... nigra Willst. Pile of abdomen partly light-colored. ................... .2 2. Light-colored pile on basal 4 or 5 tergites. ... orcina Wied. Light-colored pile on first 3 tergites: always black on 4th.. .. .3 3.
Wings light yellowish-brown. .............. bomboides Wied. Wings dark purplish-brown. .......................... .4
4. 3rd joint of antenna length of arista: male genitalia with yellow hair. ............................. chrysomela sp. n. 3rd joint of antenna subequal to arista in length: male genitalia with black hair. .................... .rex sp. n. A table is also included, showing points of contrast in the case of the four species whose characters make them difficult to distinguish.
Length measurements of the body do not mean
192 Psyche [June
a great deal in this genus, as the abdomen may be contracted in some individuals and distended in others. A better basis of comparison is the wing measurement.
Mallophora rex, sp. nov.
cf 9 -Length of body, 26-33 mm. (A series of 86 M. bom- boides from Florida gave lengths from 23-29 mm.) Similar to
bornboides in habitus. Mystax composed of dense yellow bristles below, black above. Beard, light yellow. Palpi, black with yellow hairs and a few black ones. Antennae dark brown. Pile along ant'erior border of prescutum and lateral anterior angles of thorax, yellow.
A strip of yellow pile extending from
base of wings to metacoxse.
Scutelluin covered with a dense
mass of long yellow pile. Other hairs of thorax black. Wings dark purplish brown. Legs dark reddish-brown, densely covered with short, stout black hairs. The hind femur
with a very few inconspicuous yellow hairs intermingled. The
under side of the hind tibia of the cf bears a small tuft of white pile.
In five specimens from N. Carolina the venter of the ab- domen is covered solely with black hairs; in the five other spe- cimens from which the description was drawn (three from Miss- issippi, one from N. Carolina, and one from'Florida), there is a median line of light yellow pile, broadening toward the apex of the abdomen where it clothes the sixth and seventh segments. The first three tergites bear dense yellow pile. The remainder of the pile on the abdomen is black. The hairs on the male claspers are black.
Habitat. Three specimens from the collection of the Miss. Agricultural College, received from Professor Harned. Newton
Co., Mississippi (Aug. 1920) (E. Blackburn) ; Iuka, Miss. (J. N. Miller); Leaksville, Miss. (Aug. 20) (0. 2. Smith). Four spe- cimens from Southern Pines, N. c., three of which were taken Aug. 1907, and one 1, 7, '89 (A. 13. Manee coll.) received from Mr. Nathan Banks; and two from the collection of the Ameri- can Ent. Soc., courtesy of Mr. E. T. Cresson, Jr. The Data on the latter are: one from "Florida," and one from Southern Pines, N. Carolina (VIII, 26, '09) collected by A. H. Manee.
19251 Brems Resembling Mdllophorce of Southeastern U. S. 193 Mallophora chrysomela, sp. nov.
$-Length of body 23-27 mm. Thick, heavy hairs of mystax, beard, palpi, occiput, gem, and post-gens bright yel- low; a very few black hairs intermingled with the yellow on palpi.
On the meso-thorax a patch of yellow pile extends cephalad from the base of the wings to the prothorax which is also covered with yellow pile. There are a few yellow hairs along the anterior margin of the prescutum. Scutellum covered with thickly set, long yellow pile. A narrow area of long yellow hair extends from a point below and slightly posterior to the base of the wing, to the metacoxa. Wings dark purplish brown. Legs reddish- brown, densely clothed with black hairs. Some yellow pile on hind femora, and a thick patch of silver hairs on the inner side of the distal portion of the hind tibia. Pro- and meta-cox8 with yellow hairs intermingled with a few black ones. Abdomen with first, second and third tergites with thick yellow pile. Venter with a median area of yellow pile, narrow anteriorly but widening posteriorly to cover entirely the sixth and seventh segments, where it becomes darker in color, ap- proaching orange. Other hairs on abdomen black. Hair on male claspers yellow.
Habitat. Two specimens from Gulfport, Miss., Sept. 11, 1916 (C. C. Gieer), one from Ship Island, Miss. (9-6.20) (B. L. Collins). All three from the collection of the Miss. Agricultural College, examined through the . kindness of Professor Harned. Another (6-30-06) from Atlanta, Georgia, from the American En$. Soc. Coll. Philadelphia, Pa., examined through the kindness of Mr. E. T. Cresson Jr.
Of the species discussed above, the following are pictured in Howard's Insect Book.
Mallophora orcina (Wied.) Plat*e XVII, fig. 21 and 23. M. bomboides (Wied.) Plate XIX, fig. 22. M. fautrix 0. S. Plate XVIII, fig. 3.
194 Psyche [June
TABLE OF MALLOPHORA OF THE BOMBOIDES GROUP. orcina
rex, sp. n.
23-24 23 .;
ello ow dark
hairs on under-
legs I...... side of
black. c? 's black
tuft on under
side of hind
tibia and dis-
tal joints of
largely white largely
black. 3's black ir
with silver some; in
uft on under others,
side of hind black
Mostly black largely
Some yellow yellow
on hind femur
Silver tuft on
~nder side of
lind tibia in
I or 5 ter-
)lack in some
:ases ( c? 's)
ipical 2 seg-
yte yellow on
ipical 2 seg-
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