130 Mittheil. d. Münchener Ent. Ver. 1881. 
exist in the Diptera calyptrata, in the Asilidae ete. They 
are often stubble-shaped. £ 
B. Thoracie dorsal bristles. 
I divide the thoraeie dorsum in regions, as they are indieated by the 
existing structural features: the dorsal stripes, indicative: of the 
position of the longitudinal thoraeic muscles, and the thoracie 
transverse suture (or rather furrow), separating the anterior from 
the posterior bundles of the vertical museles.. Thus we obtain: 
the dorso-central region in the middle (III), and the dorso- 
humeral (I) and dorso-alar (II) regions on each side. This divi- 
sion will be found very convenient for localiziing auy bristle we 
may have to describe. — These roman numerals will be sometimes 
used by me to represent the corresponding regions Thus supra- 
alar hristles (II), will mean supra-alar bristles (dorso-alar region). 
I. Dorso-humeral region. It is bounded by the anterior end 
of the thorax and the thoracic transverse suture on two sides, and by 
the dorso-pleural suture and dorso-central region on the two others. I 
distinguish here: ; 
1. The humeral bristle (Loew, Europ. Helomyziden), in- 
serted on the humeral callus; in the Acalyptrata either one, or none 
at all; in the Calyptrata often several. 
2. The post-humeral bristles, as far as I know, with rare 
exceptions Zwo, inserted immediately above the dorso-pleural suture, 
between the humeral callus and the root of the wing; both are in- 
serted at the bottom of the praesutural depression, a triangular de- 
pression which usually exists here in the Cyelorhapha. 
3. A praesutural bristle, immediately in front of the thoraeic 
suture, above the praesutural depression. It is »0o& found in the Or- 
talidae, but oceurs in most Trypetidae, Sciomyzidae, Sapromyzidae. 
It may be homologous with a bristle in the same place in the Diptera 
Calyptrata, but which is less conspicuous among the other bristles 
which they have in the same region, and which I call ntra-humeral. 
The Asilidae possess very characteristic and persistent praesutural 
bristles (two or more). 
The Acalyptrata, as far as I am aware, have no other bristles 
in the dorso-humeral region. The Diptera Calyptrata have several 
bristles besides, which may be called the intra-humeral®bristles. 
