INSECTA. 319 



Sepsis FALL., MEIG. (Cephalia MEIG.) Antennge shorter than 

 head. Head elongate. Eyes rotund. Abdomen quadriannulate, 

 narrow. Wings erect, vibrating. 



Sub-genera: Chelig aster MACQ., Nemopoda ROBIN., Michogaster 

 MACQ. 



Diopsis L. Eyes very remote, the head being produced on both 

 sides into a transverse petiole, oculiferous at its apex, and before the 

 apex antenniferous. Antennae short, with three joints, the last 

 suborbicular with a long naked seta. Scutellum bispinose, two or 

 four other spines at the sides of the thorax. 



Comp. A. DAHL, prseside C. LINN.EO Bigce Insectorum 1775, Amcenitates 

 Acad. vui. p. 303. PI. vi. figs, i 5 (reprinted in FUESSLY, Archives de 

 I'Hist. des Ins. pp. 19, 20, Tab. 6); DALMAN, Act. Holm. 1817, Analect. 

 Entomol. No. i. (OKEN'S Isis 1820) ; J. O. WESTWOOD, On Diopsis, Trans. 

 Linn. Soc. xvni. 1835, pp. 283 312, pi. See also figures of two species 

 of this genus in GUERIN, Iconogr., Ins. pi. 103, figs. 8, 9. 



LINN^US described only one species of Diopsis (Diops. ickneumonea), 

 now about twenty are known. They are all exotic and from the old world 

 (west coast of Africa, India, Java) ; Diopsis brevicornis SAY, WIEDEM., a 

 species from Pennsylvania, seems not to belong to this genus. According 

 to WESTWOOD there are four setae in the sucker in Diopsis Sykesii, as in 

 Syrphus. These small *lies by their pediculated eyes remind us of Podophtkal- 

 mus LATE., amongst the Crustacea, and of Zygcena, amongst the fishes. 



Calobata MEIG., Micropeza LATE. 

 Micropeza FALL., Calobata LATE. 



Tanypeza FALL., Tceniaptera MACQ., Nerius FABE., WIEDEM. 



Longina WIEDEM. Antennae longer than head, with first joint 

 longest. 



Thyreophora LATE,, MEIG. 



Actora MEIG. 



Ccelopa MEIG., (Psalidomyia DOUMEEC). 



Comp. DOUMERC, Mtm. sur le Psalydomyia fucicola, diptdre vivant sur 

 les lords de la mer, Ann. de la Soc. Entom. IT. 1833, PP- 89 93. The 

 male has at the abdomen a forceps almost like that of the Forficulce, but 

 with obtuse and hairy points. 



Ulidia MEIG., Mosillus LATE. 



Gymnopoda, MACQ., Lipara MEIG., Timia MEIG. 



