of Buprestidae and Elateridse. 189 



although a slight indication of it may be found in some cases, 

 where the posterior part of the epimeron is somewhat bent out- 

 wards. It is even very rare to find the pronotum and epimera pro- 

 thoracica separated by a real suture (as in Carabidse) ; nay, it often 

 occurs that the sutures between the pronotum, prosternum, and the 

 epimera become to such a degree effaced that the entire prothorax 

 seems to consist of only one piece (as in most Curculionidse). In 

 Buprestidae and Elateridse all these parts are immoveably united, 

 but the seams between the prosternum and epimera are always 

 to be recognized, and the junction of the epimera and pronotum 

 is marked by the more or less sharply raised lateral edges of the 

 latter. It follows that the Buprestidae possess no episterna on 

 the prothorax, any more than any other insect, unless that ap- 

 pellation is to be given to the large lateral shields themselves 

 which are commonly called epimera. Von Kiesenwetter regards 

 the true epimera as laterally inflected parts of the pronotum, 

 and gives the name of episterna to the prolongations of the 

 prosternum (which other authors equally erroneously call tro- 

 chantins), and thus he comes to the result that the prothorax in 

 Buprestidae consists of pronotum, episterna, and prosternum, 

 but in Elateridae of pronotum and prosternum alone (Nat. Ins. 

 Deutl. iv. p. 217), whereas the prothorax in both families con- 

 sists of the same pieces as in other insects, viz. pronotum, pro- 

 sternum, and epimera prothoraciea, as shown before. 



VI. 



Anybody who has watched nature a little in field and forest 

 knows full well that faculty in the Elateres which has procured 

 them the popular name of spring-beetles. It would therefore 

 be natural to expect that the peculiar contrivance by means of 

 which these beetles are enabled, when placed on their back, to 

 toss themselves up in the air and fall down on their legs, had 

 long ago been so thoroughly investigated and understood by 

 scientific entomologists that it could always -with certainty be 

 decided whether any given species is endowed with this faculty 

 or not. But this is very far from being the case : it is still a 

 moot point with regard to many animals of the Elater-type 

 whether they can spring or not, so that, generally speaking, one 

 is not satisfied till one has seen the thing done before one's own 

 eyes ; and with regard to this mechanism there is but little agree- 

 ment amongst entomologists, except concerning the cases where 

 the articulation of the prothorax and mesothorax is sufficiently 

 loose to allow us to inspect easily the whole structure and pro- 

 ceeding. This latter has been familiar for a very long time; and 

 short and correct accounts of it are given in old manuals, as 

 by Latreille in Cuvier's ' Regne Animal.' It is true that some 



