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X. StriduJating Organs in Coleoptera. By Charles 

 J. Gahan, M.A. 



[Read March 7th, 1900.] 



Plate VII. 



In the course of my work on tlie Coleoptera I have had 

 occasion from time to time to note the occurrence of 

 stridulating organs in these insects. Some of my observa- 

 tions appeared to be new, but instead of offering these as 

 a separate contribution, I thought it might be more 

 useful to include them in a general account of the subject. 

 This I have endeavoured to give in the present paper. 

 Tlie stridulating organs of beetles, so far as they were 

 known at the time, have been very adequately dealt with 

 by Darwin in his " Descent of Man," and the account 

 which he has there given of them still remains one of the 

 most complete. Landois also, to whose researches we owe 

 a great part of our knowledge of these oi-gans, has given 

 a very full and detailed history of them in liis "Thier- 

 stimmen," published at Freiburg in 1874. But it was 

 not until that same year that the first account appeared 

 of the remarkably well develoj^ed stridulating organs 

 which Schiodte discovered in the larvro of several genera 

 of beetles ; and this, together with the further observations 

 which have been made by others since that date, have 

 somewhat considerably increased our knowledge of the 

 subject, and have added fresh interest to it. Had Schiodte's 

 discovery been known to Darwin it might, perhaps, have 

 led him to modify his view that stridulation in beetles 

 serves as a sexual call, and that the organs by which it is 

 produced have reached their present state of development 

 by a process of sexual selection. If adult beetles alone 

 had to be considered there would be little o-pound for 

 objectmg to this view. But it is quite evident that the 

 stridulating organs must serve some other purpose in 

 the larvse, and that sexual selection could have had 

 nothing to do with their development; and if this be 

 true of the larvse there is no reason why it should not be 

 true also in regard to some at least of the adult forms. 

 TRANS. ENT. SOC. LOND. 1900. — PxVRT IH. (OCTOBER) 



