1917] Phytogeny of the ElateridcB 201 



That this classification is on a much firmer basis than one 

 depending entirely upon adult morphology, needs no con- 

 firmation. Many taxonomists have questioned the advisability 

 of attempting to apply to the insects the axiom of the general 

 zoologist, that ontogeny bears out phylogeny, that is to say, 

 that the history of the race is borne out by recapitulation in 

 the history of the individual. They contend that, though 

 undoubtedly the evolution of the race leaves its impressions 

 upon the successive stages in the ontogeny of the extant rep- 

 resentative of that race, the insect larva is so actively associated 

 with its environment that adaptive variations will entirely 

 obliterate these phyletic inheritances. Though this is undoubt- 

 edly true in a certain degree, and must be considered when 

 reviewing larval characters, it has been overstated, at least in 

 the Elateridas. Representatives of nearly all the tribes are 

 found in a variety of habitats much more diverse than the 

 habitats of many families of mammals, yet they retain the 

 phyletic characters so as to leave no doubt whatever as to 

 their relationship. For example, larvae of the genus Melanotus 

 are found in rotten logs, in cultivated fields, under stones, 

 in forest moss, and in mud. No one would question the 

 relationship of the various species of Melanotus, and their 

 larvae, even under these extremely different habitats, are almost 

 inseparable. Larvae of the genus Elater are found in rotten 

 logs, in the stems of mushrooms, under stones, and under 

 lichens on exposed boulders, yet an Elater larva can be recognized 

 at a glance, and no important phyletic characters have been 

 obscured by adaptive modifications. I believe it more logical 

 to accept ontogenic evidence, with reasonable reservation, 

 than to blindly follow adult comparative morphology, without 

 taking into consideration the enormous possibility of error 

 on account of convergent variation due to the fact that the 

 adult Elaterids are much less diverse in habits than are their 

 larvae. As far as we know their habits, they all frequent 

 flowers and leaves and are exclusively phytophagous, while 

 the larvae live in practically all habitats, except the truly 

 aquatic, and are both carnivorous and phytophagous. 



The Schematic tree (Fig. 10) is arranged to express my 

 concept of the phylogeny of the Elateridae, of which the larvae 

 are now known. The vertical elevation of the origin of the 



