Most of these specimens have been referred to by Ormiston 

 already (I.e.), and have been presented by him to the B.M. 



Horned Beetles. — Mr. G. J. Arrow showed a series of 

 lantern slides to illustrate different types of armature occur- 

 ring in Lamellicorn Beetles, and made the following remarks :- 



Various theories have been put forward to account for 

 these armatures. Darwin (" Descent of Man ") believed they 

 could be best explained by Sexual Selection, i. e. by the exercise 

 of a preference on the part of the females for males with the 

 best-developed horns. This theoretical preference was sup- 

 ])orted by no evidence of its actual existence in insects, and 

 it is doubtful if any entomologist could be found to profess 

 belief in its existence to-day. 



Sexual Selection was rejected by A. R. Wallace, who sug- 

 gested (" Tropical Nature," 1878) that horns in beetles might 

 be explained as a means for making the bearers less easily 

 swallowed by certain birds — ^the males being more active 

 than the females, would be' more liable to such risks, and 

 therefore in greater need of such protection. But, whilst 

 some horned beetles are very tiny and their horns extremely 

 delicate, others are so huge that their size is sufficient to 

 prevent any bird swallowing them whole, and moreover 

 many of the males of these giant forms show by much more 

 conspicuous coloration, etc., than that of the females that 

 it is the latter, and not the males, to which special protection 

 is accorded. 



Reichenau (Kosmos, 1881) put forward the theory that 

 the supposed rudimentary horns of the females were the 

 really important structures, serving as implements for excava- 

 tion, and that, whilst of no use in the other sex, they had 

 been inherited from the female and had developed to an 

 exaggerated extent. 



Lameere (Bull. Acad. Belg., 1904) believes that horns were 

 formerly possessed by all Lamellicorns, even Stagbeetles, 

 Cockchafers, etc., but that they have in many cases been 

 replaced by other forms of sexual dimorphism. He considers 

 their special development in the males to be a form of com- 

 pensation for the reproductive energy expended by the females. 

 These various theories are all attempts to explain the more 



