IQ PROCEEDINGS OF THE NATIONAL MUSEUM vol.68 



Length, 5 to 8 mm. 



Type.— Male, Cat. No. 28150, U.S.N.M., from Stone Valley, 

 Pennsylvania. 



Described from the following material, all males: In the National 

 Museum; one from White Mountains, New Hampshire (Morrison); 

 four from Stone Valley, Pennsylvania, June 24 (H. E. Ewing) ; 

 seven from Pluramer Island, Maryland, bred from nest of Trypoxylon 

 politum, February 2.5, 1917 (H. L. Viereck); one from Kaslo, 

 British Columbia (K. P. Currie) : in tlie Canadian National collec- 

 tion, two, Barber D., New Brunswick, 24-vi-1914 (F. M. McKenzie) 

 (J. D. Tothill); one. Barber D., New Brunswick, 25-vi-1914 (J. D. 

 Tothill); one, Hamilton River, Muskrat Falls, Labrador, 12-19-vii- 

 1919 (S. E. Arthur) : in the collection of R. C. Shannon, one from 

 Ithaca, New York, May 25, 1922. 



The female, I have been unable to distinguish from those of P. 

 signafus. The male also resembles signatus excepting in the genitalia 

 which is widely different. P. distortus is at present known from 

 only a limited number of localities in the northeastern states, eastern 

 Canada, and from Kaslo, British Columbia. It has never been 

 collected on flowers. Doctor Ewing secured several specimens from 

 a large number observed flying about the porch of a deserted cabin 

 in Pennsylvania. It has been reared from Trypoxylon politum Say. 



Genus SENOTAINIA Macquart 



Senotainia Macquart, Dipt. Exot. SuppL, vol. 1, p. 167, 1846. Genotype, 

 rubriventris from Galveston, Tex., not seen; but the original description 

 mentions the presence of a frontal row of eight bristles, three orbitals, 

 a linear frontal vitta and red abdomen, distinctive of one common North 

 American species widely recognized as rubriventris. — Coquillett, U. S. 

 Bur. Ent., Tech. Ser., No. 7, p. 80, 1897; Proc. U. S. Nat. Mus., vol. 37, 

 p. 605, 1910.— Adams, in WiUiston's Diptera of N. A., p. 373, fig. 152, 

 no. 110, p. 375, {Miltogramma), 1908. — Townsend, Smithson. Misc. 

 Coll., vol. 51, p. 56, 1908; An. Ent. Soc. Amer., vol. 4, p. 140, 1911. 



Megaera Robineau-Desvoidy, Myod., p. 94, 1830. According to Bezzi 

 and Stein, (Pal. Dipt., vol. 3, p. 515) preoccupied by Wagler for Reptilia, 

 in August 1830, (Lsis, 1830, p. 944). No date other than 1830 appears in 

 Desvoidy's publication. 



Sphecapata Rondani, Dipt. Ital. Prod., vol. 3, p. 221, 1859. Genotype not 

 designated by Rondani. S. albifrons Rondani designated by Brauer 

 and Bergenstamm, Denkschr. Akad. Wien., vol. 56, p. 115, 1889. S. 

 conica Fallen designated by Brauer, Vorarb. Monog. Muse. Schizo., p. 

 58, 1893. But since albifrons equals conica, (Bezzi and Stein, Kat. 

 Pal. Dipt., vol. 3, p. 515) the latter becomes the genotype. After careful 

 examination of European specimens of conica determined by Professor 

 Bezzi and others, I am unable to distinguish any characters of generic 

 importance separating this species from Senotainia. 



Misellia Robineau-Desvoidy, Dipt. Env. Paris, vol. 2, p. 146, 1863. 

 Genotype designated is Megaera dira Robineau-Desvoidy which according 

 to Desvoidy's own statement^ equals_;Afi//ogro7« wo conica Fallen. But 



