THE ANDROCONIA OF CALLIDRYAS FLORELLA. 303 



fore wing. Part of the base of each wing is more thinly clothed 

 with scales than the remaining portion, the two parts being 

 abruptly divided, so as to be plainly seen with a pocket-lens. 

 One is almost inclined to believe that some of the scales forming 

 the general covering have been requisitioned to form the andro- 

 conial patch, but as there is no ''patch" on the upper wing such 

 an explanation would scarcely be adequate. The scales of the 

 patch seen by transmitted light are dark coloured, and like most 

 highly specialized scales are rounded, or without pectinations at 

 their apices ; the striae are very fine, owing to this and the 

 opacity of the scales they are not readily seen; by reflected 

 light they appear white and highly polished ; the scale-walls 

 are seen to be thrown into longitudinal folds, as if partially 

 emptied of their contents ; the hairs of the brush have rounded 

 apices, and seem nearly black by transmitted light. 



The structures described above form a good example of what 

 are known as *'Androconia," and are supposed to be the agents 

 employed in the production and diffusion of odours ; but a little 

 consideration will show how closely they resemble stridulating 

 organs ; it is probable that they may serve both purposes, the 

 friction between the brush and patch promoting the diffusion of 

 scented vapours or particles, at the same time producing sound, 

 which although inaudible to our ears may nevertheless have a 

 real existence. I do not wish to deny the association of these 

 structures with scent-producing powers, but the alleged existence 

 of the odours seems to rest mainly on hypothetical considerations ; 

 on the other hand, the movements of the brush over the up-turned 

 ends of the scales forming the patch must produce vibration, 

 therefore sound must necessarily be evolved. 



May not a word be said in favour of the visual organs of the 

 butterfly in question. If its senses of smell and hearing are 

 gratified, or if they in some measure conduce to its well-being, 

 why may not its power of sight also perform its part? The 

 aigrette-like plumes of the brush form what to us are very 

 graceful objects. Are the owners of them denied a similar 

 gratification ? They may be unable to have a satisfactory view 

 of their own individual adornment, but surely they can see those 

 of their fellows ; and the sight of these ornamental plumes is 

 probably appreciated by the female portion of the florella popula- 

 tion. Androconia, such as I have endeavoured to describe, are, 

 I believe, generally regarded as guides to enable one sex to more 

 readily discover the near proximity of the other sex. This seems 

 a false view of their function ; but if we regard the odoriferous 

 emanation as productive of sexual excitability, we can understand 

 that a similar result may be achieved by means of the senses of 

 eight and hearing ; all three senses, in this species, performing 

 their parts in promoting its well-being. 



3, Halifax Koad, Cambridge. 



