DIPTERA. 281 
Curysoroxum, Meig.—Mulio, Fab. 
Where the seta is also inserted on the third joint but near its base; 
this joint is the longest of all, and forms a narrow and elongated 
triangle; the two others are almost of equal length. The wings are 
distant(1). 
Sometimes the seta, always thick and in the form of a stilet, ter- 
minates the antennz. 
Cerra, Fab. 
Where the body is oval, elongated, and resembles that of a Wasp; 
the second joint of the antennz is of equal length with the last, and 
forms with it a fusiform club with avery short stilet. The abdomen 
is long and cylindrical. ‘The wings are very remote, and the exte- 
rior cell of the posterior margin has a well-marked re-entering angle 
in the outer edge(2). 
CatiicrerA, Meig. 
Where the body, shorter, wider and silky, has the general ap- 
pearance of that of the common Fly. The second joint of the an- 
tennz, shorter than the last, forms with it an elongated, compressed, 
fusiform and slightly arcuated club; the seta is in the form of an 
elongated stilet; the first joint is longer than the following one. 
The exterior cell of the posterior margin exhibits no emargination 
in its sides(3). 
The nasal tubercle which distinguishes the preceding Syrphide, 
disappears in the following ones. ‘ The seta of the antenne is almost 
always simple. ‘The wings are incumbent, one on the other. 
The first are connected with the preceding ones by the length of 
their antenne. Those organs are closely approximated at base; the 
second joint, the shortest of all, forms, with the third, a narrow 
and elongated club; the seta is simple and inserted near the base of 
the latter. 
(1) Item. - 
(2) See Fab., Lat., Meig. and Wiedemann. 
(3) See Lat., Meig. 
Vou. [1V.—2 L 
