DIPTERA. — ACROCERIDE. 545 
leading to those of Nemestrina, which in some species are very much 
reticulated (fig. 128.19. wing of N. longirostris). The species of 
this interesting group are exotic, especially frequenting hot localities. 
M. Westermann has observed that N. longirostris (in which the pro- 
boscis is at least three times as long as the entire body, and ex- 
ceedingly slender, and which is an inhabitant of the Cape of Good 
Hope), solely resorts to the species of Gladiolus, of which it. sucks the 
honey with its long snout, which just equals the length of the tube of 
the flower; when unemployed, the proboscis is directed back beneath 
the body (Silberm. Rev. Ent. No. 3.). 

The family AcRocERIDE* (fig. 128. 20. Ogcodes gibbosus), also 
forming part of the Linnzan genus Musca, is of small extent, and 
composed of insects generally of small size, having the body short 
and thick, the abdomen being round, and very much swollen ; whence 
these insects have been termed Vesiculosa. The thorax is very 
elevated, with the wings deflexed ; the winglets are very large, cover- 
ing the balancers. The antenne ( fig. 128. 21.) are very minute, and 
inserted close together ; and the proboscis either long and bent 
beneath the body, or obsolete. The eyes are very large, and occupy 
the major part of the head, which is, however, so minute, and attached 
so low, as to be almost invisible from above. The veins of the wings 
are variously and singularly arranged, and sometimes very indistinct. 
The species exhibit a general degree of weakness in their construc. 
tion. Their movements are slow; and they are found upon plants, 
and amongst flowers. The species are but few in number, and chiefly 
exotic. Their larvee have not been observed. In a preceding page 
(p: 189.) Ihave noticed the curious fact, observed both by the Senator 
Van Heyden and M. V. Audouin, of the very rare Ogcodes gibbosus 
being selected by a species of Crabro, which burrows in wood, as the 
food of its progeny. 
The true situation of this family, in a natural system, is very 
difficult to be determined. 

* Bretiocgr. Rerer. TO THE ACROCERID&. 
Lamarck, in Ann. du Mus. d’Hist. Nat. tom. iii. (Panops). * 
And the general works of Mezgen, Wiedemann, Macquart, Griffith (An. Kingd.), 
and Perty (Del An. art. Braz.). cae 
VOL. II. NN 
