134 GENERIC SYNOPSIS. 
Family 9. (or 15.) MYDASIDZ Westw. (Mydasii Latr. My- 
dasidez p. Leach.) 
There is no British species of this family. 
Family 10.(or 16.) THEREVIDE Westw. (Xylotome Meig., 
Mcq, Mydasidex p. Leach. ) 
THEREVA Latr. Nemoretus p. D. G. 11 sp. Musca plebeia L. 
Antennz as long as the head, terminal joints elongate-conic ; style 2-jointed. 
Meig. pl. 15. f. 8. 
Family 11. (or 17.) ZLEPTID/E Westw. (Leptides Meig., 
Mcq. Rhagionidze Leach. ) 
LEPTIS Meig. Ruacio Fab. 8 sp. M. scolopacea Linn. Curt. 705. 
Palpi incurved ; style of antenne terminal. 
CHRYSOPILUS Meg. Lerris Fab. 5sp. L. Diadema Linn. Curt. 713. 
Palpi recurved ; style of antenna terminal. 
ATHERIX Meig. Lerris p. Fab. 5 sp. L. Ibis Fab. Curt. 26. 
Palpi porrected ; third joint of antennz very short, semiglobular; style dorsal. 
Obs. Spania, referred to this family by Macquart and Haliday, differs in 
having only 2-jointed antennz. 
Family 12. (or 18.) DOLICHOPIDZ Leach. (Dolicho- 
podes Mezg. ) 
MACHZRIUM Hal. ——-—-- lsp. M. maritime Hal. Z. I. pl. 15. f. 11. 
Third joint of antenne very long, excised beneath; apex linear; style short, 
2-jointed ; eyes apart ; wings parallel, incumbent. 
DIAPHORUS Meig. ———— 2sp. JD. flavo cinctus Hoff. 
Antenne with third joint patelliform,:with a dorsal villose seta; eyes confluent ; 
abdomen ¢ with two filaments at the tip; wingsincumbent, parallel. Meig. 
pl. 34. f. 8. 
PSILOPUS Meig. Doticuorus p. Fab. 7 sp. D. platypterus Fab. 
Antenne with third joint patelliform, villose, with a dorsal villose deflexed seta ; 
eyes apart; wings incumbent, parallel, with a curved transverse nerve at the 
tip. Meig. pl. 34. f. 14. 
CHRYSOTUS Meig. Doticnorus p. Fab. 9 sp. D. nigripes Fab. 
Antenne with third joint patelliform, villose, with an apical, villose, deflexed seta ; 
eyes apart; abdomen ¢ with two filaments at the tip; wings incumbent, sub- 
divaricate. Meig. t. 35. f. 10. 
RHAPHIUM Meig. ——— 5sp. R.longicorne Meig. Curt. 568. 
Antennz approximate, with third joint in ¢ elongate, compressed ; style subapi- 
cal, 2-jointed ; eyes not confluent ; wings incumbent, parallel. 
PORPHYROPS Meig. Doticnorus p. Fab. 28 sp. D. diaphanus Fab. 
Antenne, with third joint oblong-acute, with a villose deflexed seta ; eyes apart ; 
abdomen ¢ with two filaments; wings incumbent, parallel. Curt. 541. 
Obs. Mr. Haliday retains P. diaphanus as the type of his subgenus Por- 
phyrops, but Macquart gives it as that of his genus Argyra.  P. pallidus 
Meig. is the type of Haliday’s subgenus Plectropus ; and P. riparius Meig. 
that of his subgenus Perithinus (2. J.) 
