Broad-headed flies (Eurychoromyidae), the rarest family of flies

Eurychoromyia mallea

Eurychoromyia mallea is the rarest known fly. Eurychoromyia mallea was described from 4 specimens collected in Bolivia in early 1903. This species has not been seen nor collected since then. Two of the specimens are now in the Naturhistorisches Museum Wien (Vienna, Austria) in the Hendel Collection under the care of Dr. R. Contreras-Lichtenberg. The other specimens are in the Schnuse Collection in Staatliches Museum fur Tierkunde (Dresden, Germany).

While there are many species of Flies known from an unique specimen or a single collecting event, what makes mallea unique is that mallea is the sole representative of a higher group, a distinctive type of fly. This is equivalent, for example, to saying manatees were known only from 4 specimens once collected in the Florida Everglades.

Broad-headed Flies
are 5 mm
long, with the head 2.5 mm wide. Their coloration is shiny peach-brown.
Nothing is known of the habits and habitat of broad-headed Flies. Hence, their economic importance of is also unknown.

Broad-headed Flies are the rarest Flies known, having been collected by only one person at one place during early 1903. The only known locality (Sarampiuni) is in Bolivia in the foothills of the Andes, some 80 miles due north of La Paz.

MapSerampiuni map

Immature stages (eggs, maggots & puparia) are unknown.

The family Eurychoromyiidae consists of a single genus and species, Eurychoromyia mallea Hendel. What is known of these flies is summarized here. Facsimile copies of the two major papers devoted to them are also provided (see references).

As there is only one genus and one species of Eurychoromyiidae, we have combined the genus and species pages with this family page.

Family relationships

Eurychoromyiidae has always been considered distinct from other higher Flies (group Acalypterae) and has been clustered close to the Lauxaniidae and Chamaemyiidae. Griffiths (1972) placed it as the sister to Chamaemyiidae. McAlpine (1989) placed it as the sister to Celyphidae, which together formed the sister-group to Lauxaniidae.

Family Diagnosis

The family is defined by its a) distinctive head shape and structure, b) elongate antennal scape, c) precoxal bridge and d) 4 spermatheca. Other significant characters (from McAlpine 1989: 1447) are: 1) main bristles of head and thorax reduced or lost; 2) fronto-orbital plates broadly enlarged, largely obliterating the frontal vitta; 3) fronto-orbital plate demarcated from parafacial area by a lateral extension of the ptilinal suture; 4) face strongly convex; 5) ocellar triangle small, ocelli very closely crowded together; 6) scape elongate, longer than pedicel; 7) proboscis stout with broad labella; 8) mesonotum broader than long; 9) pleuron short, higher than long; 10) black costal setulae reduced; 11) abdomen short and broad, dorsoventrally compressed; 12) preapical dorsal tibial bristles lost; 13) hind tibia broadened and flattened; 14) gonopods and parameres indistinguishably fused and greatly reduced; and 15) aedeagal apodeme absent.

As noted by McAlpine (1989) Eurychoromyiidae shares characters 1-11 & c with Celyphidae, but is distinguished from Celyphidae by characters 13-15 & d.

Genus and Species description

For nomenclatural details, see Prado (1975)


We are indebted to Dr. Ruth Contreras-Lichtenberg of the Naturhistorisches Museum Wien for allowing us to post the excellent color images of Euchoromyia, which were done by W. Zelenka. These images are the property of the museum, which holds the copyright.


Griffiths, G. 1972. The phylogenetic classification of Diptera Cyclorrhapha, with special reference to the structure of the male postabdomen. Ser. Ent. 8, 340 pp. Dr. W. Junk, N. V., The Hague. [1972.06.??]

Hendel, F. 1910. Ueber acalypterate Musciden. Wien. Ent. Ztg. 29: 101-127. [1910.02.28] Facisimile copy available
Translation of section on Eurychoromyiidae available

Hennig, W. 1958. Die Familien der Diptera Schizophora und ihre phylogenetischen Verwandtschaftsbeziehungen. Beitr. Ent. 8: 505-686. [1958.??.??] Translation of section on Eurychoromyiidae available

Hennig, W. 1973. 31. Diptera (Zweiflugler). In Helmcke, J.-G., Starck, D. & Wermuth, H. (eds.), Handbuch der Zoologie. Eine Naturgeschichte der Stamm des Tierreichs. IV. Band. Arthropoda-2. Halfte: Insecta. Zweite Auflage. 2. Teil. Spezielles. W. de Gruyter, Berlin. [3]+ 337 pp. [1973.10.??]

McAlpine, J. F. 1968. Taxonomic notes on Eurychoromyia mallea (Diptera: Eurychoromyiidae). Can. Ent. 100: 819-823. [1968.08.22] Facisimile copy available

McAlpine, J. F. 1989. Phylogeny and classification of the Muscomorpha. Manual Nearctic Dipt. 3: 1397-1518, [1989.03.15]

Pires do Prado, A. 1975. Family Eurychoromyiidae. Cat. Dipt. Am. S. U.S. 65A, 1 p. [1975.10.30] Facisimile copy available

Technical Notes

1. Following is a translation of Hennig (1958: 599-600) done for Canada Agriculture by Harder, G. H.

Hendel described (1910) Eurychoromyia mallea Hendel from Bolivia as "isolated group- type of acalyptrate Muscidae." He points out several conformities with the "Sciomyzinae" but is unable "also here to wedge in our genus."

The 4 female specimens described by Hendel seem to be the only thing that hitherto is known of this species. With the kind permission of Mr. Reichert, Dre. Hertel and Draeseke I was able to examine more closely a type of the Museum in Dresden. On the basis of this (Figs. 27F, 151, 156, 165) it seems to me that as the closest relatives of Eurychoromyia only the Lauxaniidae and Chamaemyiidae can be considered as the closest or nearest relatives of Eurychoromyia. Eurychoromyia in conformity to the Chamaemyiidae has 4 spermatheca (Fig. 27F), which is a very rare characateristic in the Schizophora. Otherwise there is nothing disputing the assumption of a close affinity of the Eurychoromyia with the Chamaemyiidae. But as long as the male is unknown one cannot regard a statement concerning the possible affinities of Eurychoromyia as definitely established.

2.The type-locality of Eurychoromyia mallea is Sarampiuni, not "Sarampioni" as spelt by Hendel nor is it a collector as thought by McAlpine. Sarampiuni is a village on the Rio Sarampiuni, a tributary of the Rio Mapiri. The collector was C. A. W. Schnuse.

3.The name Eurychoromyia is derived from the Greek words: "eurys" for broad; "choros" for land or country; and "myia" for fly. One of the most striking characters of the fly is the broad head. Hence, the use of the word "choros" does not make any sense until one realizes that there was already a Eurycephalomyia! Hence, I have introduced the common name, broad-headed Flies, for the family Eurychoromyiidae. The specific epithet, mallea is derived from the Latin "malleus" meaning "hammer."

Content by F. Christian Thompson

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