AMERICAN TWO-WINGED FLIES OF THE GENUS 

 MICROPHTHALMA MACQUART, WITH NOTES ON RE- 

 LATED FORMS 



By J. M. Aldrich 

 Aiisociate Curator, Dirision of Insects, United States National Museum 



Flies of the genus Micro pkthahna have been reared many times as 

 parasites of larvae of May beetles of the genus PhyJI^phaga. They 

 are undoubtedly of great economic importance. A recent examina- 

 tion of the literature and of the United States National Museum 

 collections has shown that a considerable degree of confusion exists 

 in the identification of specimens. It therefore seemed advisable to 

 publish the results of these studies. 



Genus MICROPHTHALMA Macquart 



Microphthalnia Macquakt, Dipteres exotiques, vol. 2, pt. 3, 1843, p. 241. — 

 CoQUiLLETT, Revisioii of the North American Tachinidae, 1897, p. 13S. — 

 Adams, in Williston's Manual, 1908, p. 376. — Curran, Ent. News, vol. 36, 

 1925, p. 15. 



Euinicrophthalnia Townsend, Insecutor Inscitiae Menst., vol. 3, 1915, p. 97. 



Perua Townsend, Proc. U. S. Nat. Mus., vol. 43, 1912, p. 364. 



The type and sole original species is nigra Macquart; the type and 

 sole species of Eumicrophthalma is sJumnoni Townsend; and that of 

 Perua is cuzcana Townsend. 



The type species nigra has heretofore been supposed to be a syno- 

 nym of distincta. As explained farther on, I identify this as a sepa- 

 rate species, differing slightly in the form of the antennae and in 

 the presence of ocellar bristles from distincta. This modification 

 brings Micro phthcdnia so close to Perua that the latter must ap- 

 parently become a synonym. The occasional presence of small ocel- 

 lars in Microphthalma michiganensis would seem to prevent the 

 recognition of the ocellars as a generic character in this group, while 

 the other characters appear to be strictly of specific importance. If. 

 there are two genera here, Eumicrophthalma should be extended to 

 cover distincta^ michiganends^ and -fJaviceps^ as well as shaRnoni; in; 

 this case Microphthalnia will cover nigra., cmana, and townsendi. L 

 do not favor this division. 



No. 2639.— Proceedings U. S. National Museum, Vol. 69, Art. 13. 

 3040 — 26 1 



