of Buprestidse and Elateridse. 311 



Thomson has shown with much abiUty the details of this point 

 of structure in Elateridse. 



Throughout the whole series up to Campylus the ventral sur- 

 face of the abdomen retains the same peculiarities, being horny, 

 hard, arched, with sharp edges, and so composed that only the 

 last segment is moveable — a circumstance which, even in dried 

 specimens, is distinguishable by the fact that the membrane 

 between the last two segments is bare. In Campylus, however, 

 the ventral surface is flatter and softer, particularly along the 

 side edges, where it is almost quite soft, and all the segments 

 are moveable. This is in itself an indication of the power of 

 clicking having in CampT/lus become a subordinate point, as in 

 Melasini and Eucnemidini, though there it is due to a develop- 

 ment of the type in an entirely opposite direction ; for whilst in 

 Campylus the faculty of springing yields the first place to the 

 development of the legs, it is in the two groups just mentioned 

 the power of flight which is increased at the cost of the " click- 

 ing/' But in Campylus we meet also with another important 

 circumstance — namely, that the elytra do not, as in other genera 

 of this family, fit into a groove on the pronotum, but protrude 

 freely above its posterior edge. Amongst the digging Elateridse 

 or Cebrionini this arrangement is only met with in Cebrio. 

 The preponderance which, in conformity with this, is accorded 

 to the legs, shows itself in several peculiarities — for instance, in 

 this, that the fore legs cannot, as in other Elateridse, be accom- 

 modated inside the hind corners of the pronotum, which there- 

 fore are continued backwards in the form of a spout. These 

 remarkable and important peculiarities in the structure of Cam- 

 pylus have hitherto been overlooked ; and thus it has not only 

 been classed together with such genera as Hemiops and Plectro- 

 sternus, with which it has in reality nothing to do, but authors 

 have even placed in the genus Campylus itself such species as 

 E. homalismus, Illig., and others, which do not resemble C. line- 

 aris or C. denticollis in anything except in general outline and 

 habitus, but entirely difiPer from them in the structure of the 

 sternum, limbs, and abdomen, and therefore must find their 

 proper places in other genera of Elateridse. 



Besides Campylus there is one other Danish genus of this 

 family in which the pronotum is not arranged for receiving the 

 base of the elytra in its hind margin, and in which, therefore, in 

 like manner the springing-joint is without the essential support 

 afforded by this articulation. Campylus shows by its whole 

 structure that this want is connected with a reduction of the 

 springing-faculty in all points, and an increased development 

 of the limbs. We might therefore at first sight be surprised to 

 find the same want of support in the articulation in a genus 



15* 



