HETEROGONY AND TAXONOMY 213 



throughout considerable groups of animals. What we have 

 just been saying about systematics has an immediate bearing 

 upon certain evolutionary problems. For we should then 

 expect to find heterogonic organs varying in their relative 

 size with absolute size of body in different-sized species of the 

 same genus, or different-sized genera of the same family, just 

 as in different-sized individuals of the single species. Our 

 supposition is confirmed : this does occur. It is not universal 

 or inevitable, but it does occur frequently. 



The rule was independently discovered by Lameere (1904 ; 

 seealso 1915) and Geoff rey Smith (1906B), and numerous further 

 instances of it have been put on record by Champy (1924 



Fig. 94. — Phenomenon of Lameere and Geoffrey Smith in species of the 



Dynastid beetle Golofa. 



Below, two specimens of G. porteri. 



Above, right, G. cczcum ; left, G. imperialis. 



and 1929) : Lucanidae (1924, pp. 142, 152) ; Dynastidae (ibid., 

 pp. 152-4) ; and see Fig. 94. 



In the most striking cases, the heterogonic organs in the 

 males of the large species are relatively enormous, while in 

 those of the small species they are scarcely more developed 

 than in females (e.g. Fig. 94 ; the beetle Golofa porteri against 

 G. imperialis, Champy, 1929, p. 230). This at first sight appears 

 as an example of orthogenesis ; but if orthogenesis be taken 

 in its strict sense, of a determinate evolutionary change in 

 the germ-plasm, this is not so. All that we have is a type 

 of growth-mechanism, which, if not modified, will yield certain 

 predictable results, as regards relative organ-size, with any 

 given absolute body-size. If a new high or low extreme of 

 body-size, not previously attained in the evolution of the 



