320 INSECTA, 
discovered the two others in the same Insect. ‘They are 
situated, as in other Diptera, near the origin of the halteres. 
The abdomen of the Hippobosca ovina—see Melophagus— 
presents ten, in the form of little round, corneous, umbili- 
cated tubercles, the four last being approximated to the anus. 
Those of the thorax, always four, are very apparent. Ac- 
cording to the same observer the interior of this part of the 
body in the H. eqguina presents both utricular and tubular 
trachez ; but those of the abdomen are all of the latter de- 
scription and very numerous. 
The wings are always distant and accompanied by halteres. 
Their edge is more or less fringed with cilia. ‘The superior 
nervures which are in its vicinity are strong and very dis- 
tinct; but those which then extend to the posterior margin 
are but slightly marked and are not united transversely. In 
the last Diptera of this family, these organs are wanting or 
are merely rudimental. ‘The halteres also disappear. ‘The legs 
are very distant and terminated by two robust nails with one 
or two teeth beneath, which makes them appear double or 
triple. The skin of the abdomen is formed of a continuous 
membrane, so that this part of the body is susceptible of being © 
distended and of acquiring a considerable volume, as necessa- 
rily happens in those female Hippobosce, where the larve are . 
hatched and continue to reside until the period of their trans- 
formation into pup. At this epoch the larva issue from the 
venter of the mother in the form of a soft, white egg, almost 
as bulky as the maternal abdomen; the skin hardens and be- 
comes a firm shell, at first brown, then black, round, and fre- 
quently emarginated at one end, and presenting a glossy plate 
or operculum which is finally detached in the manner of a cap 
to allow the egress of the perfect Insect. This shell has no 
annuli or transverse incisures, a character which distinguishes 
it from the other pup of Diptera, and from those of the 
Athericera particularly, to which it approximates the most. 
It is to the splendid Memoirs relative to these Insects by - 
Reaumur, De Geer, and M. Leon Dufour, all accompanied 
by detailed figures, that we must recur, in order to obtain a 
