Ins. 235 
DIPTERA. 
BY 
W. F. Kirby, &c. 
The General Subject. 
Bellesme, 'Jousset de. Recherches exp^rimentales sur les fonctions du 
Balancier chez les Insectes Dipteres. Paris : 1878, 8vo, pp. 95, 
woodcuts. 
The writer begins by describing the structure of the halteres, and 
quoting from Kiinckel d’Herculais the opinions of previous authors as to 
their functions. He then discusses the phenomena of flight and the con- 
ditions most favourable to accurate experiment, and details the results 
of experiments. The removal of the halteres renders flies incapable of 
flight ; if more than half is removed, they describe a parabola, and fall 
on their backs, and fall in a similar manner after the first effort if they 
attempt to rise from a plane surface ; and slighter mutilations affect the 
flight more or less considerably. He then discusses the phenomena of 
the flight of insects, and concludes that the removal of the halteres affects 
the centre of gravity, and thus renders the insects incapable of ascending 
flight. 
Bigot, J. M. F. Dipteres nouveaux ou peu connus. Ann. Soc. Ent, Fr. 
(5) viii. pp. 31-48, 213-240, 401-446. 
The characters of the genera PyrelUa, Rob. Desv., and Ocyptera, Latr., 
and the various families and genera of Asilidcs are discussed. The follow- 
ing notes occur: — Laphria posticata, Macq., is distinct from that of Say ; 
Volucella evecta, Walk., is an Eristalis. 
iVIiK, J. Dipterologische Untersuchungen. JB. Ak. Gymn. Wien, 1878, 
pp. 26, pi. i. 
A large number of new genera and species of Dolichopodidm^ and 2 new 
Empidm are described. 
PoRTCHiNSKY, I. Materiaux pour servir h I’histoire de la faune Russe 
et Caucasienne. Les Dipteres bombiformes. Troudy Ent. Ross. x. 
pp. 102-198, pi. iii. 
A long paper, almost entirely in Russian, but a few new species and 
varieties are diagnosed in Latin, and tables are given of the various 
Bombi and Diptera which resemble each other. 
