EXTERNAL ANATOMY OF INSECTS. 675 
Rutelide, &c. though in others they are implanted :—of 
the second, in the cubitus of the Mantida, and of all the 
tibie of the dragon-flies (Libellulina)? ;—and of both 
kinds in the hind-legs of Acrida, those which arm the 
upper angles of the tibiz being processes, and those of 
the lower being zmplanted. ‘The term spine I think 
ought to be restricted to the first kind; the second ought 
rather to be denominated spurs (calcarvia), and may 
perhaps be regarded as in some degree synonymous with 
those most important appendages of the joint in question, 
that are implanted in or near their apex, which have 
been hitherto distinguished by this last denomination, 
and which I am next to consider. But though I have 
not altered a term generally adopted, I must here ex- 
press my opinion that they ought rather to be considered 
as minute foes or fingers, and that the denomination best 
agreeing with their functions, as accessories to the main 
toe, would be digituli: this is proved particularly by a 
character peculiar to those of many species of the genus 
Cimbex amongst the saw-flies, in which these organs are 
furnished with a sucker or pulvillus (as they are also in 
(inas a kind of blister beetle), as well as the joints of the 
tarsi’; which makes it evident that they are applied by 
the animal to surfaces, and assist it in walking or climb- 
ing; and in general it may be observed that in most in- 
sects their principal use is connected with these motions, 
and with burrowing. This circumstance tends to prove 
* It is remarkable that in this tribe a// the legs may be called 
raptorious, though the thighs are not incrassated, for they are armed 
with a double series or more of fine long spurs, which enable them 
to catch and retain their prey. 
> Prare XXVIL. Fic. 35, o'”’. Philos. Trans. 1816, t, xix. f. 8, 9. 
See above, Vor. II. p. 327. 
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