586 EXTERNAL ANATOMY OF INSECTS. 
of slender, vertical, straight processes, fitted with a 
broad cartilaginous plate at their apex, rises from the 
endosternum, and sends forth a lateral one to the side of 
the medipectus: and lastly, in Carabus the medifurca is 
represented by a pair of subtriangular lamnie attached 
to the sides of the trunk. 
3. Postfurca*. This, which belongs to the hind- 
legs, is the most remarkable of the pectcral processes, ° 
and has been noticed by more than one writer>. It is 
a kind of trident, the branches‘ of which are acute, and 
on their upper surface longitudinally concave, elevated 
on a footstalk¢ inclined towards the medifurca, consist- 
ing of two plates, a posterior one supporting the lateral 
branches, and an anterior ay interior one forming a right 
angle with the other, supporting the intermediate one. 
This footstalk rises from between the posterior core, 
which appear in the Lamellicorns to ginglymate with it at 
its base. ‘The middle branch of the trident dips to the 
sinus of the medifurca. In Dytiscus marginalis the form 
is different; for the intermediate branch consists of two 
parallel pieces, and the lateral ones are dilated into broad 
vertical plates: the stalk of this is triquetrous, and a tri- 
ple cartilaginous partition appears to go from its base 
anteriorly, the lateral ones diverging to the sides of the 
trunk, and the intermediate one running straight to the 
base of the medifurca. 
It may not be without interest to state here some of 
the several objects and uses of this structure of the 
trunk. When our Saviour says to his disciples, “ But 
* Prate XXII. Fic. 5. 5 +. 
> MacLeay, Hore Entomolog. 9. Chabrier Sur le Vol des Ins. 
c. i. 417. ° Pare XXII, Fic. 5. b b b. 4 bid. c. 
