204 



• 1 N TJtO DUCT I ON. 



trochanters. Not much has been added to our knowledge of the 

 stridulatory organs of the larvae since the work of Schiodte was 

 published, but numerous further observations with regard to the 

 stridulatory organs of the perfect insects have been made by 

 Mr. C. J. Gahan (Trans. Ent. Soc. Lond. 1900, pp. 433-452, 

 pi. vii) and Mr. G. J. Arrow (Trans. Ent. Soc. Lond. 1904, 

 pp. 709-750, pi. xxxvi). Mr. Gahan's is a general paper, but he 

 describes several species of Lamellicornia as possessing vocal 

 organs in the perfect state. Mr. Arrow's important paper is 

 entirely devoted to the Lamellicornia, and is full of interesting 

 details, but we have no space here to go fully into the question. 

 We quite agree with him when he says that " the special import- 

 ance of stridulation in the Lamellicorns is probably in part due to 

 a mental development higher than that of most other beetles, and 

 evidenced, not only by the concentration which here occurs in 

 the nervous system, but in certain cases by a degree of social 

 organization which was, until quite recently, hardly suspected, 

 although the elaborate instincts of certain members of the group 

 attracted attention in very early times, and procured from the 

 ancient Egyptians peculiar honours for the sacred Scarabaeus and 

 other beetles of the same family." 



Apart from mere structure, it is the possession of these instincts, 

 and the greater development of the nervous organization, as evi- 

 denced by the stridulatory powers of the larvse, that induce us to 

 regard the Lamellicorns as in the first place a perfectly separate 

 series or sub-order, and in the second place as holding the highest 

 position in the order of the Coleoptera. It should, however, be 

 noticed that the stridulatory powers are by no means so general 

 in the perfect insects as in the larva3, although occasionally the 

 imago has stroug vocal powers (as in Tro.v) which are quite 

 wanting in the earlier stage. 



We really know very little of the phylogenetic history and the 

 interrelation of the group, and authors are greatly at variance 

 with regard to it. Thus Lameere (Ann. Soc. Ent. Belgique, xliv, 

 1900, p. 371) says that, as the Lucanid.e possess live visible 

 ventral segments, they cannot be the ancestors of the Scarab^id^;, 

 Avhich possess six ; Ganglbauer (Munch. Koleopt. Zeitsch. i, 3, 

 1903, p. 312) points out that Lameere is here assigning too high 

 a phylogenetic value to the number of the abdominal segments ; 

 these, he says, are five in number, if the elytra entirely cover the 

 abdomen, whereas they are more than five if the apex of the 

 abdomen is uncovered, and he regards the unshortened elytra as 

 characteristic of the primary type. 



Again Ganglbauer believes that the extraordinary development 

 of the thoracic horns, so conspicuous in many of the males of the 

 large series, is derived from forms that did not possess the sexual 

 dimorphism ; whereas Lameere is of opinion that the reverse is 

 the case, and that therefore the Dynastin.e are the primitive 

 Pleurostict forms. The latter author regards the modifications of 

 sexual dimorphism as the key-note (Leitmotif) of the evolution 

 of the Lamellicorns ; whereas Ganglbauer would find it in the 



