DIPTERA. 243 
Aspisres, Hoff. Meig. 
The only Insects of this division which have but eight joints in 
the antennz, the last forming an ovoid club(1). 
All the following Diptera, a small number excepted, have 
their antenne composed of three joints, the first of which is 
so short, that it may be excluded from the supputations; the 
last is annulated transversely, but without distinct divisions. 
It is frequently accompanied with a seta, usually lateral, and 
situated on the summit in others, presenting two joints at 
base, sometimes simple, and sometimes silky. When this 
seta is terminal, it frequently happens that its length dimi- 
nishes and its thickness increases, so that it has the form of a 
stilet. Although this piece may be considered as a continua- 
tion of the antenne, yet as it is separated from them, and 
appears to constitute an appendage, to deviate from the course 
generally adopted, by adding to the ordinary number of the 
antenn those of the seta, would only disturb the harmony of 
our nomenclature. ‘The palpi never have more than two 
joints. 
Some, a few excepted, whose larve divest themselves of 
their skin previous to becoming pup, always have a sucker 
composed of six or four pieces; the proboscis, or at least 
its extremity, that is to say, its lips, is always salient. The 
palpi, when they exist, are exterior, and inserted near the 
margin of the oval cavity, close to which arises the sucker. 
The larva, even of those in which the skin forms a cocoon 
for the pupa (Stratiomis), retain their primitive form. 
This subdivision will comprise three families. 
(1) Idem. 
