Thorax in winged Insects. 161 
4, The epimera of the prothorax are not in general so much developed 
as the episterna, but may be known by being often inferiorly situated, 
and always in some connexion with the coxe. M. Audouin has ob- 
served that they often articulate with the coxze by means of a small inter- 
vening piece which he calls the trochantine. This piece is similar to 
the trochanter, which terminates the coxa at its other end. 
I may here observe that when the stigmata of the prothoraz, or any 
other thoracic stigmata, are surrounded by asmall horny piece, M. Au- 
douin calls this the peritremas* 
Or THE MESOTHORAX. 
The mesothorax of an insect has, when at its maximum of develope- 
ment, four pieces to the tergum (which is the mesothorax of Kirby) and 
eight to the pectus (which is the medipectus of Kirby). 
The four superior or tergal pieces of the mesothorax are the prescu- 
tum, scutum, scutellum and postscutellum,+ so named according to their 
order from the head of the insect. 
1. The prescutum is the anterior, as its name denotes. It is the pro- 
phragma of Kirby. 
2. The seutum is a very important piece, often greatly developed, and, 
according to M. Audouin,§ always articulating with the bones of the 
or lateral margin of the prothoraz, where this is terminated by the episternum 
and epimeron, “La réunion de l’episternum, du paraptére et de l’epimére 
“ constitue les flancs.’”? The only names that are useful, however, are those 
which denote the pieces of the thorax; all others only burden the science, It 
is just as clear, for instance, to talk of the side of the prothorar as of its 
pleura or ora, 
* Very possibly the pnystega of Kirby is Audouin’s peritrema of the meso- 
thorax, 
+ It ison this account that when a sternum is at its maximum of develope- 
ment I name its four pieces, presternum, sternum, sternellum, and poststernum. 
f See Int. to Ent., Tab. 22, fig. 8. h’. 
§ Iam inclined to differ with M. Audouin on this head, and think that the 
scutum does not directly articulate with the wing, but by the intervention of 
two lateral pieces, which I would call the parapsides. These are in general 
soldered together with the scutum, but in many Hymenoptera, such as Chalcis, 
&c,, they are particularly distinct. 
Von, V. L 
