Thorax in winged Insects. 173 
which passes a ligament which this author calls the funiculus, and which 
serves, as he correctly says, to support the abdomen. The two lateral 
apertures are false, being formed above by the two horny lobes of the 
interior of the horse-shoe, and below by the membrane which forms one 
side of the passage for the intestines from the thorax to the abdomen. 
The aperture of the thorax which forms this passage is best seen by turn- 
ing up the metathorax, when it will.be observed to be terminated by a 
lozenge-formed section laterally widest, having the trochlea in front, the 
two sockets for the legs at the sides, and the passage for the intestines in 
the middle. 
5. The paraptera are small trapezoidal pieces which intervene be- 
tween the prscutum of the metathorax and the sockets of the under 
wings. In general the paraptera belong to the pectus; but as in our 
insect they are situated above the wings, I have thought it best to describe 
them in this place.* 
Or THE PECTUS. 
The order of Hymenoptera is in general so essentially flying that the 
tergum of the whole thorax undergoes, as we have seen, a very great de~ 
velopement, which of course occasions the pectus to be very little deve- 
loped as to size, except in Ants and other tribes which are essentially 
walkers. This part of our investigation therefore will be proportionably 
difficult, although I think the excellent principles of M. Audouin will 
enable us to surmount the difficulty. 
1. OF THE PEcTUS OF THE PROTHORAX. 
The pectus is diminished in size, as I have said, owing to the great de- 
velopement of the mesothorax. But typically it ought to consist of six 
pieces, viz. 
1, The sternum of the prothorax in Polistes is narrow, and I know 
no better way of describing its shape than as resembling a sand glass 
placed on an escutcheon.t According to Mr. Kirby’s definition, the 
whole matter perfectly explained without the intervention of either wheels or 
pullies. Ihave represented the postscutellum of Polistes in figures 5 and 7. 
* Fig. 5, O. + Fig. 8, U. 
