268 INSECTA, 
Pacuystomus, Lat. 
Where the antenne are composed of three joints, the last of which 
is divided into as many rings(1). 
In the second section, that of the Decatoma, Lat., we find 
antenne always composed of three joints, the last of which, 
the longest, without stilet or seta, and divided into eight 
rings, is clavate in some, and almost cylindrical or in the form 
of an elongated cone in the others. The wings are usually 
incumbent on the body. ‘The tarsi are furnished with three 
pellets. 
These Insects may be united in one generic section. 
XYLOPHAGUS. 
In some, the antennz are much longer than the head, with the two 
first joints very short and the third very long, compressed, forming 
a strangulated club, slightly geniculate in the middle, the inferior 
portion resembling an elongated cone, and the other an oval palette. 
The scutellum is unarmed. 
Hermetia, Lat. Fab.(2) 
The antennz of the others are never much longer than the head, 
and terminate by an almost cylindrical or elongated and conical 
joint. 
Here, the scutellum is spineless. 
XyiLopuacus, Meig. Fab. Lat. 
Or Xylophagus proper, where the body is narrow and elongated, 
(1) Lat., Gener. Crust. et Insect., IV, 286; Encyc. Méthod., article Pachystome. 
The larva of the P. syrphorde; Panz., Faun. Insect. Germ., Ixxvii, 9, the female; 
lives under the bark of the Pine; its pupa resembles that of a Tabanus. 
(2) See Lat., and Fab. 
