The Bionomics of South African Insects. 408 



terrifying cliaracter, or it imy bo really aposematic for 

 certain mammals and birds, to which it may bo distasteful. 

 I cannot find from other sources that the Kafirs here have 

 any superstitions with regard to it ; the only insects they 

 take any interest in seem to be the various beetles and 

 larvae which they eat. 



26. Insect Stridulation as a Warning or Intimidat- 

 ing Character. (G. A. K. M.) 



Sedislmry, April 19, 1901. — I have been thinking of 

 trying to get some material together to support the view 

 that stridulation in insects where occurring in both sexes 

 may be explained in a large number of cases as a warning 

 character, its value in this respect being especially well 

 brought out in a number of obscurely-coloured Hetero- 

 mera, etc., which are known to be distasteful, while it is 

 largely absent in brightly-coloured, distasteful groups, as 

 CetoniidiV, MyktbridiV, Lycidai, etc. I should also expect 

 to find it more prevalent among distasteful nocturnal 

 species, where warning colours are of little avail. One of 

 my chief difficulties lies in tlie larval stridulating organs 

 in Coleoptera referred to by Gahan in his interesting 

 paper (Trans. Ent. Soc. Lond., 1900, p. 433), and I 

 should be much interested if you could kindly tell me 

 whether these larvae really do stridulate, for I see that 

 Sharp (Camb. Nat, Hist. Ins., Vol. II, p. 198) throws much 

 doubt on the larval stridulation of Melolonthidm and Sceira- 

 htvidx suggested by Schiodte. Luennus cervus seems to be 

 a well-authenticated case, and it would be most interesting 

 to know whether the larva is distasteful. Darwin's sug- 

 gestion as to the acquirement of stridulation by one sex 

 and its subsequent transference to the other has always 

 seemed to me unsatisfactory, and its possible warning value 

 occurred to me immediately I began experimenting with 

 Coleoptera. Of course in some cases it might be pseud- 

 aposematic, as in Hymenoptera-like Longicorns in which it 

 would suggest the shrill, angry buzz of a wa.sp. Pocock 

 has already suggested this explanation with reference to 

 scorpions and Mygale spiders, but I am not aware of any 

 one else having referred to it. 



[For this interesting investigation a piece of apparatus 

 invented for me by my friend Mr. G. J. Burch, F.R.S., would 

 be extremely useful. It consists of an ordinary double 



