15 
to the description which they ought to do, serve only to perplex 
by their perfect disagreement. His generic characters of this 
genus are also false, as though made by guess more than exami¬ 
nation. 
It has been doubted whether these animals possess any mouth : 
Linnaeus expressly says, “Os nullum punctis tribus but when 
the hairs are removed, which in every species very much obscure 
the parts of the mouth, two clavated palpi are seen, and between 
them the opening of the mouth ; and by laying open the vesicular 
or inflated part of the face, the continuation of it is visible in 
the form of a membraneous haustellum, which is generally co¬ 
loured with some dark brown matter lodging on the inside ; though 
I confess, after repeated dissections, I have not been able to trace 
this haustellum farther than the inside of the inflated part of the 
head, where it appears to enlarge and terminate. 
Fabricius has minutely described labia to the haustellum , and 
other apparatus to the mouth, which I have not been fortunate in 
obtaining a sight of. At the same time I cannot help being sur¬ 
prized that he should have overlooked the palpi, which he ex¬ 
pressly denies the existence of, though tolerably visible even 
without the aid of glasses.* 
He added also to his enumeration the Oe. Trompe and the Oe. 
Pecorum., and one or two of the American species of Bots, or 
rather subtercutaneous flies, which on more minute inspection we 
are induced to separate from this genus, and form them into a 
new family, under the generic title Outerebra, three species oi 
which we propose to give, for the first time with figures. 
After Fabricius, Professor Gmelin published an enlai'ged edi¬ 
tion of the Systema Naturae, and collating from all quarters, vastly 
enlarged in appearance the extent of this family ; but unfoi tu- 
■* Fabricii Genera Insectoruia, 
