246 INSECTA. 
In the two following subgenera the antenne ‘are manifestly longer 
than the head, and frequently placed on acommon pedicle; the stilet 
is elongated and of the same thickness as the antenna, at the end of 
which it forms two joints, the second longest, almost cylindrical or 
ovoid, and terminating in an obtuse point. In 
CrraturcGus, Wied. 
The antenne are not implanted on acommon tubercle, and their 
first joint is shorter than the second(1). In 
Dioorria, Meig. Fab. 
These organs are situated on a common peduncle, and their first 
joint is longer than the following one(2). . 
There, the terminal stilet of the antennz is prolonged i in the form 
of a seta. 
Those in which this seta is simple form the subgenus’ 
- AsILUs proper. 
In Europe towards the close of summer we frequently find the 
A. crabroniformis, L.3 De Geer, Ins., VI, xiv, 3. It is about 
an inch long, and of an ochre-yellow; three first abdominal an- 
nuli of a velvet-black, the rest fulvous-yellow; wings russet. 
The metamorphosis of this species as well as that of the 4. for- 
cipatus, Lin., has been carefully observed(3). 
Those, in which the seta of Ee antenne is plumous, form the sub- 
genus 
(1) Ibid., Anal. Entom., pl. i, 5 
(2) The same authors. 
(3) For the other species and these various subgenera, see Latreille, Meigen, 
Fabricius, Wiedemann and Macquart. I presumed that the genus Cyrtoma of 
Meigen should not be ‘arranged with the Platypezine, but with the Empides, 
according to the opinion of Fallen. M. Macquart has in fact lately referred them 
to the latter. This subgenus is distinguished from all those of this division, fur- 
nished like it with biarticulated antennz, and in which the palpi are incumbent 
on the trunk, by the elongated and conical form of the last joint of the antennz, 
by the wings, and by the smallness of the palpi. For other details, see Macquart’s 
work, Dipt. du nord de la France. 
