190 Prof.' J. C. Schiodte on the Classification 



German naturalists (particularly Burnieister 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 antennse, pressing 

 them closely to the body, so that as little 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 mesosternuni, 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 point 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. It 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 tiie 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 com[)letely 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 being 

 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 



