DIPTERA. ' 251 
the abdomen is triangular or conical; the proboscis is directed for- 
wards. 
Their antennz always consist of three joints, the last elongated, 
almost fusiform and compressed, truncated or obtuse, usually ter- 
minated bya very short stilet, and never by an elongated seta. The 
palpi are small, slender and filiform. ‘The proboscis is generally 
very long and most slender at the extremity. Their legs are long 
and attenuated. They fly with great velocity, hover over flowers 
without alighting on them, introduce their trunk into their calyx to 
obtain their nectar, and produce a sharp humming sound. I sus- 
pect that their larve are parasitical as well as those of the following 
genus. 
In some the proboscis is evidently longer than the head, very 
slender and tapers to a point. 
Toxornora, Meig. 
Removed from all the others by the antennz, which are as long 
as the head and thorax, projecting, filiform, and terminating in a 
point, and of which the first joint is much longer than the rest. 
The body is elongated(1). 
Of those in which the antenne are much shorter, the 
Xestromyza, Wied. 
Approximates to Toxophora in the length of the first joint of 
those organs, which is considerably greater than that of the others; 
it is almost fusiform, as well as the third or last(2). 
‘ 
Aparomyza, Wied. 
Is another subgenus in which the first joint of the antennz is also 
very long; but here that joint is cylindrical(3). 
In the following subgenera of the same division, or of those whose 
proboscis is long and setaceous, or filiform, the last is the longest. 
Sometimes the two first joints of the antenne are short and almost 
of equal length. 
(1) See Meigen; his 7. maculatus had been described and figured by Villers, 
in his Entom. d’Europ., III, x, 31. Asilus fasciculatus. See also Wied., Dipt. 
Exot. 
(2) Wied., Dipt., Exot., 153, I, 11. 
(3) Id., Ibid., III. I have never seen a species of this genus. 
