The Flies of the Genus Meromacrus (Syrphidae) by Frank M
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AMERICAN MUSEUM NOVITATES Published by Number 1200 THE AMERICAN MUSEUM OF NATURAL HISTORY October 19, 1942 New York City THE FLIES OF THE GENUS MEROMACRUS (SYRPHIDAE) BY FRANK M. HULL' The genus Meromacrus contains large In carrying forward this study I have and handsome New World flies belonging been greatly assisted by the loan of ma- to the group Eristalini and distinguished terial from Dr. C. H. Curran, who placed by broad form, bare eyes and usually before me all undetermined material of spots and fascia of bright tomentum. this genus in the American Museum col- Most of the species are found in the Neo- lections and for this help I especially thank tropical region. In recent years the genus him. I also wish to thank Dr. C. L. has been studied by Hine, Sack and later Fluke of the University of Wisconsin, and by Curran. S. H. de Souza-Lopes of Rio de Janeiro In presenting this key to the species I for the loan of material. Types unless have been fortunate in studying thirty-one otherwise stated are in The American species. I am not certain that funereus Museum of Natural History. Shannon represents a species distinct from niger Sack, and a type examination will KEY TO THE SPECIES OF Meromacrus be necessary to determine this. I have 1.-Very dark, black or almost black flies; included two species in the key upon the no conspicuous markings upon thorax or basis of the valuable illustrations in Sack's abdomen; loop of third vein filled with study. As far as I am aware, of all of the brown color along its inner margin, with or without a clear sinus above ....... 2. described species, only ghiliani Rondani At least the thorax or abdomen, or both, (Brazil) is omitted from the key. There with yellow or brownish yellow or white are thirty-five known species. spots or fascia of tomentum. Thorax with The species fall into several groups on at most a single median vitta and short submedial, anterior vittae; more often the basis of the presence or absence of the non-vittate; loop of third vein always median mesonotal vitta, the sutural stripe, clear........................ 5. the submedial vitta and the arrangement 2.-Hind femora extraordinarily massive and of tomentum upon the abdomen. Another much thickened ......... melmoth Hull. type of be constructed upon the Hind femora thickened but not extraor- key might dinarily............... 3. basis of that group, the males of which 3.-Thorax patterned with deep velvety black have long pile-tufted venters, coxae and behind the humeri, above root of wing femoral bases. To such belong the species and along the transverse su-ture and on anna Curran, aemulus Williston, linea- anterior border of scutellum; third antennal joint broadly rounded ...... 4. scripta and melmoth Hull, fucatus Hull, Without these deep black areas; antennae potens Curran, cinctus Loew, brunneus, elongate, third joint pointed.......... new pluto and hinei, new species, and perhaps .................... pluto, species. involve a 4.-Antennae entirely light reddish brown; others. This would likely key hind trochanters with only short pale to each sex when the males of all species pile.............nigerSack. are known. For the better study of these Third antennal joint darker than the basal hairy forms I suggest the subgeneric term joint; hind trochanters with some long pale hairs in addition to the short pile. Metameromacrus. .funereusShannon. .................... Meromacrus vittata Hull does not 5.-A continuous transverse stripe or band properly belong to Meromacrus, and I across or bordering the suture of the have erected a new genus elsewhere for dorsum of the thorax, usually conspicu- its reception. ous but sometimes barely visible to the naked eye ...... .......... 11. ' University of Mississippi. With only a spot of bright tomentum on 2 AMERICAN MUSEUM NOVITATES [No. 1200 the outer end of the transverse suture, the legs chiefly orange, or, if dark browin, rarely at both ends, or none at all upon the abdomen is extensively golden the notopleura and transverse suture. .6. pilose 14. 6.-No prescutellar band of yellow tomentum Confluences of these bands barely rouinded, or pile; no sutural or notapleural spots; almost rectangular; apical half of handsome large black flies, the meso- anterior tibiae and their tarsi blackish; notum opaque, velvety black with only femora chiefly dark brown obscuira Hine. humero-medial spots. .. bruneri Curran. 14.-A broad, silky, golden, pilose band running Prescutellar band or triangle, or other down the middle of the dorsum of the bright pile, present, sometimes quite abdomen from first to fourth segmenits, narrow 7. inclusive; pile of fourth segrnent wholly 7.-Four bright yellow spots along the trans- golden yellow; fore and hind tibiae verse mesonotal suture, two upon each setaceous yellow pilose............... side ................... decorus Loew. ...................auriferus,new species. Sutural yellow spots confined to a single Without such band and pilosity 15. pair (one on each side of the thorax) at 15.-Sutural stripe continuous; hind feiiiora the outer ends of the suture, or absent. 8. brownish red; fore and hind tibia with 8. Notopleuiral spots very small or absent, considerable black setaceous pile (French fir-st abdominal segment with a yellow Guiana) ................. milesia Hull. tomentose fascia, sometimes prominient; Sutural stripe broken in the rniddle, leaviing aniterior margini of wing strongly colored the notopleural stripe, itself connected brown .10. with the humeral spot, disconniected Notopleuia with large conspicuous yellow from the short yellow fascia lying aloing tomentose spots; abdomen similarly the inner end of the suture which is maculate but not before the base of the cornfluent with the submedial vitta.... third segment; anterior margin of wing ..................... .basigeraWalker. dilutely brown but not conispicuous in 16.-The median stripe joinis the prescutellar contrast to the remainder of the wing. .9. fascia almost at ight angles; mediani 9. Fourth abdominal segmnent shining, steel vitta slender, fourth segmeint with two blue, the abdominal base dark........ yellow fascia abdominalis Sack. potens Curran. The median stripe forms a hollow sided Fourth abdorninal segment shining, steel triangle just before the scutelluiim; blue, the abdominal base light brick red. median vitta wider 30. cinctuts Loew. 17.-With an inconspicuous linear mediami vitta 10.-First abdominal segment with a con- on anterior third of thorax; abdormiein spicuous cream yellow transverse median chiefly orange brown, the pile beyonid the spot; yellow spot of anterior corner of second segment yellow; hind femora thorax linear, bright yellow, encircling light reddish ineascripta Hull. inside of humeri and reaching noto- With no yellow median vitta, though pleura.......... ......anna Curran. slender lead gray or brown vittae of First abdominal segmental spot brownish obscure pollen may be present 18. yellow, less conspicuous; anterior 18.-Abdomen everywhere reddish orange or thoracic spot likewise obscure, confined orange brown, the basal two-thirds of to the mesial side of humeri, broadly second segment and its medial poirtion disconnected from the obscure noto- throughout, as well as the posterior pleural spot hinei, new species. fourth of the third segment, black, ap- 11.-Thorax with a yellow or yellow brown pressed, stubby pilose. First segment medial stripe of tomentum upon at with conspicuous yellow tomentum along least the posterior half of the dorsum the lateral third. Mesonotum with a and confluent with the prescutellar wide, medially truncate, continuous fascia 12. transverse fascia of yellow tomentum Usually without any medial stripe of upon the suture; thick prescutellar tomentum or, if present, confined to the fascia and a pointed anteromarginal sub- anterior half or less of the dorsum and medial spot also yellow tomentose..... at least partly evanescent, or lead gray canusium Walker . ...... in color 17. Not such flies 19. 12.-With a short submedial vitta confined to 19.-Third and fourth segments of abdomen the anteirior part of the thorax and with several bright yellow transverse confluent with the sutural fascia at its bands; no bright yellow pile on first and innei (mesial) end ............. 13. second segments; thorax dark, without Without the submnedial str ipes of tomentum obvious vittae or spots... cingulata Sack. and pollen 16. Thorax usually with at least moderately 13.-Confluence of prescutellar fascia and medial conspicuous spots or fascia, or both; vitta forming a conspicuous yellowish or base of abdomen usually marked .... 20. brownish tr ianigle before the scutellum; 20.-Inner marginis of humer i with a linear, 1942] FLIES OF GENUS MEROMACRUS (SYRPHIDAE) *3 curved stripe of yellow or white pile, second and a little wider than the reaching to notopleura and sometimes elongate hypopygium; vertex pale red- connected with the linear yellow sutural dish ....... ..... gloriosus Hull. stripe.............. 32. Abdomen chiefly blackish upon the upper Thorax along the anterior margin with a surface; sides of face whitish pollinose, prominent pair of triangular, or oval the antennae brownish yellow, vertex and posteriorly pointed, yellow or white black............. flukei Curran. spots adjacent, except in opulentus Bigot, 28.-Second abdominal segment predominantly to the humeri; suture with a prominent black, with a shining steel bluish cast; yellow fascia widely interrupted in the facial stripe usually black, the antennae middle of the thorax.............. 21.