Maurice T. James.
New and Little-Known Neotropical Stratiomyidae (Diptera) in the Museum of Comparative Zoölogy.
Psyche 43(2-3):49-55, 1936.

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19361 Neotropical Stra'tiomyidz
NEW AND LITTLE-KNOWN NEOTROPICAL STRA-
TIOMYIDX (DIPTERA) IN THE MUSEUM OF
COMPARATIVE ZOOLOGY
Colorado State College
A small collection of Neotropical st ratio my id^, kindly sent to me by Dr. Nathan Banks, contained a number of interesting species, several of which are here described as new. All types are being returned to the Museum of Com- parative Zoology, Cambridge, Mass.
Monacanthella, new genus
This genus is proposed for the reception of a remarkable species which may readily be distinguished from other described Clitellariinze by the peculiar structure of the scu- tellum; instead of being unspined or with paired spines, as in other members of this sub-family, the scutellum termi- nates in a single, median, conical spine, which is elevated at a slight angle to the rest of the scutellum. The exact rela- tionship of this genus is hard to determine; in its slender form and general type of wing venation, it suggests Merin- gostylus, though the antennz are quite different. Diagnosis. Female. Eyes dichoptic, separated by two and one-half times the width of the ocellar triangle, bare; front of equal width; the face broadening out toward the oral margin. Ocellar triangle somewhat longer than wide, removed some distance from the occiput. Antennz situated somewhat below the middle of the head in lateral profile, but remote from the oral margin ; ten-segmented, the first three subequal, the subsequent ones gradually decreasing in length ; segments one and two distinct, each with a number of apical hairs on each side; segments three to seven inclu- sively distinctly separated, each segment with a subbasal hair on each side, and bearing sensory pits ; segments eight



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50 P~yche [June-Sept.
to ten inclusively indistinctly separated and without sensory pits; a subbasal hair on each side of each of these segments, and? in addition, on segment ten, a more conspicuous apical bristle and two subapical ones. Proboscis short, flattened dorso-ventrally. Mesopleura conspicuously narrowed in front. Legs elongate, the COXE three or four times as long as the trochanters. Wings slightly longer than the abdo- men; veins R 2+3 and R4 longer than, cross-vein r-m almost as long as, the width of the discal cell ; the discal cell slender, veins MI and M2 arising together at its apex; the branches of the media, cubitus, and anal veins distinct almost to the posterior wing margin; cell 2nd A elongate and definitely narrower than 1st A. Abdomen five-segmented. General body form elongate, the entire body being six or seven times as long as wide.
Genotype: MonacantheZZa g~acdis, new species. Monacanthella gracilis, new species
Female. Most of front, vertex, including the ocellar tri- angle and the ocelli, occipital orbits,, and occiput above? shin- ing black, the occiput ,below the foramen becoming brownish yellow; occipital orbits prominent ab,ove, with somewhat of FIG. 1. Monacanthella gradis, n. sp.
Antenna.
FIG. 2. A~onacmthella gracilis, n. sp.
Wing.
a bluish sheen9 narrower behind the eyes; the front just above the base of the antenn~, face, and proboscis yellow; antenn~ yellow, darkening apically. Thorax yellow? with mere vestiges of three black stripes anteriorly; minutely



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punctured or rugulose dorsally; scutellum and spines yel- low. Abdomen yellow in ground color; segments two to five inclusively with extensive blackish markings dorsally, which on segments two, four and five nearly cover the tergites, except for the lateral margins and a basal triangle on each side; the black on segment three similar, except that the apical two-fifths of the tergite is wholly yellow; venter yel- low. In addition to these segments9 four genital segments form a rather slender ovipositor which terminates in a pair of cerci that extend some distance beyond their segment. Legs yellow; the posterior femora narrowly darkened api- cally *and basally ; the hind tibi~ darkened on their inner sides'. Wings grayish brown, paler basad of the arculus and beyond vein R4; also a median pale band running from the position of the stigma across the apices of the t>wo basal cells and the base of the discal cell, and terminating in the wing margin in the fifth posterior cell ; the veins crossed by this band, including cross-vein r-m, white ; th& veins other- wise brown. Pile of entire body very sparse, yellow. Length, 7 mm.
Holotype: female, Hamburg Farm, Costa Rica, April 6 (C. W. Dodge).
Microchrysa ab,dominalis, new species
Male. Head and thorax bright metallic green, with cupreous reflections in certain lights ; antennz bright yel- low; the proboscis, humeri, wing-bases, and a region below and behind each wing base, including the pteropleura, meta- pleura, and metanotum, pale yellow, not metallic; a narrow pale yellow stripe connecting the humeri and the wing bases ; the extreme apex of the scutellum yellow ; postscutellum yel- low. Halteres yellow, the knobs whitish. Legs and abdo- men pale yellow, the latter with abundant? but slhort, appressed pile, which is black above, vellow below. Wings hyaline; stigma and strong veins yellow. Length? 3 mm.
Female. Front broader than face, metallic green. Abdo- men variable : typically, it seems to be yellow, with a strong metallic green reflection o'ver the greatest part, though two specimens seem to be metallic green in ground color, with a variable amount of non-metallic yellow basally and laterally. Otherwise as in the male.




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52 Psyche [June-Sept.
Holotype: male, Aneon, C. Z., July 15, 1924, NO. 685 (W. M. Wheeler).
Allotype : female, Los Amates, Guatemala (Kellerman) . Paratypes,: 1 male, 1 female, same data as holotype; 1 male, same data as allotype; 1 male, Gamba, C. Z., 1924 (N. Banks).
Teneral specimens, nolt designated as types : 1 male, Canal Zone, June 30, 1924 (Banks) ; 1 male, Hamburg Farm, Costa Rica, April 6 (C. W. Dodge).
Kertesz, in his catalogue of the Diptera, refers Sargus bicolor Wd. to Microchrysa, and Wiedemann's description of the species, asl far as it goes, fits abdominalis. However,
Curran (1931) has shown that S. bicolor belongs to a dif- ferent genus? quite remote from Microchrysa, which he has named Neurota. M. abdominalis is in all respects a typical Microc hrysa.
. Imsarps lateralis, new species
Related to I. texawus Melander and I. nigricornis Loew; but readily distinguished from ,both those species! by the yellow pleura. If Microchrysa nova G. T. is an Isosarguq as the description would indicate, it also belongs in this related group of species ; but, like texawus and nigricornzk, it also has) metallic green pleura.
Female.
Upper part of front and entire vertex metallic green; the pile short, pale; some longer pile, pale and black intermixed, on the vertex; the usual supra-antenna1 cross- band white; face yellow9 becoming blackish toward the oral margin; its pile short, pale. First and second antenna1 seg- ments yellow, lblack-pilose ; third segment orange ; arista yello8w, with a very few black hairs at its extreme baslea Proboscis orange. Dorsum of thorax metallic green, the humeri and extreme apex of the scutellum yellow; its pile yellowish to white; pleura yellow, the margin from the humeri to the wing-bases white ; pectus black, non-metallic. Abdomen wholly metallic purple; dorsally, with short stubby black pile? ventrally with softer, semi-appressed yel- low pile. Legs holly pale yellow; the cox= slightly dark- ened; pile coneolorous, except for a little black pile on the apical tarsomeres. Wings grayish hyaline ; venation nor-



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ma1 ; veins black ; basal section of the media, and branches MI and M3 somewhat weakened. Length, 6.5 mm. Holotype: female, Barro Colorado Island, Canal Zone, June 20, 1924 (N. Banks).
The apex of the abdomen is somewhat eaten by dermes- tids, but the specimen, except for the lack of genitalia, is not materially damaged.
Merosargus bmksi, new species
Related to ethelia Curran, but, among other thingsl, the face is wholly yellow, the metapleura are yellow, there is a prominent black spot on each mesopleuron, and the abdo- men is differently marked.
Male.
Vertex and front above black; the usual trans- verse white band broad; front below this band, and all the face, proboscis, and palpi, pale yellow. Head pale-pilose. First and second antenna1 segments yellow, black-pilose ; the third orange; arista brownish to black, bare. Front with a median, stornewhat raised, polished vitta, extending from the white transverse band to the ocelli; frontal orbits conspicuously and moderately coarsely punctured. Thorax metallic green shining on a black background dorsally, yel- lowish on the sides of the mesonotum, the black background extending to the lateral margins at the s'uture; scutellum, except the narrow apex, and metanotum, metallic green; a triangular non-metallic black spot on each mesopleuron ; otherwise yellow. Legs yellow; the apical third of the pos- terior femora black ; the posterior tibiz, except for the median third, black; middle tibiz blackish at the base. Pile of the thorax and legs pale, except for a little black pile on the apical tarsomeres. Abdomen black, with bluish or pur- plish reflections; the bases and apices of all segments yel- low; pile concolorous with the background. Genitalia yel- low. Venter brownish-yellow, with pale pile. Wings hya- line; veins black. Length, 7 mm.
Holotype: male, Barro Colorado Island, Canal Zone, June 23, 1924 (N. Banks).
Merosargus abana Curran
Three males, though considerably different fro'm the females of this species, probably ,belong here. They bear




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54 Psyche [June-Sept. .
*
the same data as Curran's types, and are associated with a female which fits his description perfectly, except that the pale pile of the mesonotum somewhat overshadows the black pile, and that the color of the meslonotum is more diluted. Structurally, the males are the same, the differences being color differences, which, in this genus, are unreliable indi- cators. The differences are as follows : Dorsum of thorax, scutellum, a spot on each mesopleuron anterior to the wing base, and metapleura black; tibiae, tarsi except the posterior basitarsi, and basal half of posterior femora, black ; first and second abdominal segments, except the apex of the latter, black; the abdomen, therefore, is black, with the narrow apices of segments two and three, and the posterior angles of four, pale.
1 female, 3 males, Sa. Emilia, Pochuta, Guatemala, 1000 m., Feb.-Mar., 1931 (J. Bequaert) .
Acanthinomyia pulchella, new species
A handsome species, readily distinguished from the other described species of this genus by the hyaline wings, the less elongate form, the more sparsely pilose eyes, the lack of an area of differentiated pile on the eyes, etc. Male. Head entirely reddish yellow, except the occiput and the ocellar triangle; the former, however, is broadly margined with yellow. Eyes reddish yellow, their pile long and moderately sparse, black on the upper, yellow on the lower half; there is no area of longer, thicker pile as in the other species of the genus. Antennae yellow, somewhat shorter than the head. Pile of head yellow, except for the longer, black pile of the vertex, and a fringe of dense, ap- pressed, silvery white pile bordering the front and face along the inner margin of the eyes. Thorax black, robust, clothed with dense, semi-appressed, straw-yellow pile, and, in addi- tion, on the dorsum, with sparse, erect, rather long", black pile; on the dorsum are four black stripes, lacking the appressed pile, which extend from the anterior margin of the mesonotum to the base of the scutellum; the two outer stripes end just beyond the outer basal angles of the scutel- lum; the median ones extend onto the disc of the scutellum and fuse there. Scutellum and its four spines black, the



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19361 Neotropical Stratiomyidss 55
latter red on their apical half, yellow-tipped; the spines are set on the definitely margined apex of the scutellum. Abdo- men black in ground color, except the apices of segments four and five, which are red, ventrally and dorsally ; a consider- able amount of black appressed pile on the median three- fourths of segments one to three inclusively, a little of this extending onto the base of segment four; segments one to three laterally, segment four for the most part, and seg- ment five wholly, with straw-yellow pile, that of the venter being entirely pale and almost white. Legs mostly blackish or reddish-black, the extreme apices of the femora and bases of the tibise, and the middle basitarsi, yellow; pile yellow, that of the inner sides of the tarsi golden. Wings yellowish hyaline, the veins distinctly yellow; cross-vein r-m very short, almost wanting, the discal cell with an appendiculate extension in that direction. Stigma distinct, yellow. Length 5.5 mm.
Holotype: male, Cordoba, Mexico (Mann).
Although this species does not agree with all the diagnos- tic characters of the genus as given by Kertesz in his Mono- graph of the Notacantha, as the foregoing description will indicate, still I can see no reason for not placing it here.



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