65 



{^^) Temnostoma exceiitrica Harris, and T. aequalis Lw. The latter, in all 

 the numerous New England specimens which I have seen, has the femora 

 black or brown, with the tips only, more or less yellow. Harris describes the 

 legs of his Milesia excentrica as " ochre-yellow, except the shanks and feet of 

 the first pair, which are black." This agrees with some specimens from Hli- 

 nois, which I have seen. These specimens have a more saturate-yellow abdo- 

 men and narrower black cross-bands than the new England specimens. But 

 why Harris' description should agree with these Western and not with the 

 New England specimens, I do not understand. The description of M. excen- 

 trica, which I prepared for the new edition of Harris' work was drawn from 

 two western males of the above mentioned species. The female which I had 

 before me at that time, was from Massachusetts, and I find now that I have a 

 second female of the same kind (from Lake Superior) ; both differ from the 

 western males (which I take for T. excentrica), as well as from T. aequalis in 

 having two yellow dots on each side of the thoracic suture (like T. alternans), 

 and not a yellow streak ; the scutellum is darker, and its pubescence is black, 

 not yellowish ; the second abdominal segment has very little yellow, etc. I 

 think that this is a distinct species, and that I was mistaken in taking it for 

 the female of excentrica. 



(2 4^ The history of this genus is as follows : 



Sphecomyia. Latreille, families naturelles, du Regne animal (1835), contains 

 the name, without any definition. The definition appeared in the Dictionnaire 

 classique d'histoire naturelle (by Rey and Gravier, publishers, in Paris), Vol. 

 XV, p. 545 (1839), as follows : 



Sphecomyia. Genre d'insectes de I'ordre des dipteres, 6tabli sur une seule 

 espec6, rapport6 de la Caroline par Bosc et tres voisine de celui de Chrysotoxe, 

 mais trfia distinct par un caractere unique dans cet ordre d'insectes, celui, 

 d'avoir la sole des insectes ins^ree sur le second article ; cet article, ainsi que 

 le precedent est long, presque cylindrique ; le troisieme ou dernier, est beau- 

 coup plus court. La sole est simple. Le genre a ete indique pour la premier^ 

 fois dans notre ouvrage sur les families naturelles du regue animal, mais 

 sans signalement, L'especd qui lui a servi de type sera consacree au celebre 

 naturaliste pr6cit6. 



Latreille never described this type of the genus, however, and it was Mac- 

 quart who saw Bosc's and Latreille's original specimen in the Museum at 

 Paris, and averred that it was the same as Chrysotoxum vittatum and Psarus 

 o.mtus of Wiedemann (Dipt. Exot. II, 2, p. 18, 1841), 



Latreille's statement that the arista is inserted on the second antennal joint 

 is, of course, erroneous. Macquart further mentions, 1. c,, that in the Berlin 

 Museum this genus figures under the collection-name of Epopter, Gorski, in 

 his Analecta ad Eutomographiam, etc., 1853, proposes the generic name Tygen- 

 tyausia for the European species of the same genus. It occurs only in Eastern 

 Europe (Sweden, Norway, Finland, Lithuania), and, as figured by Gorski, 

 certainly looks very like the North American species. Wahlberg (Ofoers 

 Vetensk. Acad. Forhandl., 1854, p. 155) gives a detailed description of it. 



(2 5) Compare H. Loew's Ceria in his Neue Dipterol. Beitriige, I (1835). 



KUL. BUF. SOC I^AT, SCI. (!)) DECEMBER, 1875. 



