DIPTERA, 349 
prison by driving off the anterior portion. See Reaumur, In- 
sect., 1V, Mem., IV and I. 
S. Reaumurti, Meig. Differing from the cuprarius in the 
abdomen, most of which, or at least the base, is of a blood-red, 
or a brighter tint of the same colour *. 
Varro, Lat., Fab.— Pacuyeaster, Merg. 
Only differing from Sargus in the antenne, which are still shorter, 
With the two first joints shorter or wider, or altogether transversal +. 
Our second general division of the Diptera, which are provided 
with a sucker enclosed in the sheath, and whose antenne consist of 
but three or two joints, comprises those whose proboscis, usually bi- 
labiate, long, geniculate, and bearing the palpi a little above the 
elbow, is most commonly entirely contained in the oral cavity, and 
when, always salient, has a sucker composed of only two pieces. The 
last joint of the antennz, always accompanied by a stilet or seta, never 
exhibits annular divisions. The palpi, when at rest, are concealed. 
This division will form our fifth family. 
FAMILY V. 
ATHERICERA, 
Where the proboscis is usually terminated by two large lips. The 
sucker is never composed of more than four pieces, and frequently 
presents but two. 
The larve have a very soft, extremely contractile, annulated body, 
narrowest and most pointed anteriorly. The head varies as to figure, 
and its external organs consist of one or two hooks, accompanied in 
some genera by mammille, and probably in all by a sort of tongue 
destined to receive the nutritious juices on which they feed. They 
usually have four stigmata, two situated on the first ring, one on each 
side, and the two others on as many circular, squamous plates, at 
the posterior extremity of the body. It has been observed that these 
latter, at least in several, were formed of three smaller and closely 
approximated stigmata. The larva has the faculty of enveloping 
these parts with the marginal skin, which forms a sort of purse, 
They never change their skin. That which invests them when 
first hatched becomes indurated, and thus forms a sort of cocoon for 
* See the same authors. © 
Wiedememann, in his ‘‘ Analecta Entomologica,’’ has figured a Brazilian species, 
the 8. furcifer, remarkable for the scutellum being armed with a long spine, forked 
at the extremity. 
+ See the same authors. 
