190 Prof. J. C. Schiddte on the Classification 
German naturalists (particularly Burmeister and Erichson), 
whose statements Lacordaire in this as in most cases implicitly 
adopts, have tried to overthrow these simple results of experience 
by means of utterly erroneous theories; but another German 
author, Von Kiesenwetter, has again returned to the true track, 
and given a correct and lucid description (Nat. Ins. Deutschl. 
vi. pp. 224-226). This, then, may be considered sufficiently well 
- established,—that if a bond -fide “skip-jack” finds himself lying 
on his back, he at once folds up his legs and antenne, pressing 
them closely to the body, so that as Tittle of them as possible 
protrudes; he then pushes back the prothorax so far that the 
point of the prosternal spine meets the salient middle part of 
the mesosternum, for which purpose it becomes necessary to 
bend the body in, so as to form an obtuse angle; the animal 
then begins to contract the flexors of the prothorax with con- 
stantly increasing force against the poimt of support on the 
mesosternum which has thus been obtained: suddenly it lets 
go; the prosternal spine glides rapidly along the groove in the 
mesosternum and down in the dip which is adapted to receive 
it; the most prominent parts on the dorsal surface of the ani- 
mal, particularly the bases of the elytra, are thereby violently 
struck against the ground, and, by the recoil, the whole body of 
the animal is tossed up into the air: while in the air, it unfolds 
its legs, in order to be able to catch a hold with its claws if it 
comes down on its legs. [t is apparent that a very free articu- 
lation between the prothorax and mesothorax is necessary for 
this operation ; and accordingly we find both the pronotum and 
the bases of the elytra steeply inclined towards the articulation ; 
it is further apparent that the prosternal spine, the prolonged 
mesosternum, with its little dip in front, its sliding plane, and 
the deep excavation at its root, play a principal part ; and from 
this starting-point a great many conclusions may be safely made. 
It is evident why the skeleton of the spring-beetle is so hard— 
because otherwise it would not possess the requisite elasticity to 
effect a sufficiently strong recoil from the ground; we perceive 
why the whole shape is moderately long and narrow, with 
rounded points in front and behind, closely fitting edges, and 
elliptical outline both in the longitudinal and cross sections, 
why all the limbs are more or less completely adapted for being 
received into grooves on the lower surface of the head, sternum, 
and abdomen, the legs for being folded up, the hip receiving 
the femur, this again the tibia, and the tibia in its turn receiving 
the foot ; finally, we see the necessity of the prothorax bemg 
long and shaped like a cushion above and below, far thicker than 
the exigencies of the muscles of the neck and legs would require. 
It is clear that in the same proportion as these arrangements 
