of Buprestidze and Elateride. 193 
Then let us take some species or other (it does not matter 
which) of the divisions of Throscide, Melaside, EKucnemide, 
Elateride, or Cebrionide, and let us lift the prosternal spine out 
of its bed on the mesothorax, and we shall find that the bed is 
not by any means constructed only with regard to that spine ; 
so that the arrangement is entirely different from that of the 
Buprestide. The place in which the prosternal spine rests 
always terminates behind in a deep excavation, which would 
be as superfluous for the accommodation of that spine as it is 
necessary for the accommodation of the ‘ springing-spine ” 
(mucro saltatorius), the essential instrument of the springing 
beetle, which has hitherto been either overlooked or misunder- 
stood, having been confounded with the prosternal spine. The 
fact is, that when the articulation of the prothorax with the 
mesothorax is not very free (that is, in most cases), the spring- 
ing-spine is, on account of the limited space, placed on the 
upper surface of the prosternal spine, forming an angle with it, 
and therefore hidden by this when the animal is viewed from 
below. It is only when drawn out by the animal for use in 
springing, or when the prothorax is entirely loosened, that it is 
seen. By degrees, as the articulation of the prothorax with 
the mesothorax is freer, and the mesothorax more salient, 
the springing-spine assumes a more horizontal direction, and 
appears behind the posterior extremity of the prosternal spine ; 
the boundary between the two is in this case marked by a small 
tooth, which is nothing but the extremity of the prosternal 
spine. Finally, in those Elaters where the joint in question is 
entirely free and open below, this little tooth also disappears, 
and with it the last indication of the original position of the 
springing-spine, which in this last case appears simply as the 
continuation of the prosternal spine. 
We shall do well to pause a few moments after having gained 
these results. We have seen that the larvee of Sternoxi group 
themselves round two distinct types, and we now see this bifur- 
cation confirmed in the perfect animals by equally decisive and 
thorough-going marks of distinction. We found the type of the 
Buprestide to be that of an animal organized for flight, that of the 
Hlateride to be characterized by the springing-mechanism. But 
the latter type is less one-sided than the former. The Buprestis- 
larva and its congeners are always xylophagous, burrowing in 
timber, and there is consequently not much room for variety in 
shape ; whether the egg is deposited in clefts of the bark of trees, 
in the tenderer stem of herbs and shrubs, or in the parenchyma of 
leaves, the demands which the propagation of the species makes 
upon the structure of the beetle remain upon the whole the 
same; but time and strength will at the same time be to such a 
Ann. & Mag. N. Hist. Ser. 3. Vol. xviii. 14 
