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vation by the same naturalist, had for him a special interest. 

 It was well known that the scent-distributing apparatus in 

 Rhopalocera took the form sometimes of specialised scales 

 scattered broadcast over the surface of the wings, as in many 

 Pierines and Lycaenids ; sometimes of scales or hairs collected 

 into definite patches, as in other Pierines and in the sub- 

 family to which Dr. Lamborn's Amauris belonged. That the 

 patch near the costa of the hind wing in Colias edusa was 

 really a scent-patch, the speaker knew from personal obser- 

 xxxvi] 



vation. In certain Pierines, as for instance Catopsilia florella, 

 in addition to a Colias-like patch on the hind wing, there 

 existed a tuft or fringe of hair-like scales near the inner edge 

 of the fore wing. The close proximity of the latter to the 

 former structure suggested that it might be used in some 

 such way as the terminal tuft of the butterfly exhibited by 

 Professor Poulton. The speaker had observed, as mentioned 

 in his Presidential Address in 1910, that the scent- patches in 

 Pierines were furnished with a special distribution of tracheae. 

 The ultimate branches of these were difficult to trace, but in 

 some instances they appeared to have an unmistakable con- 

 nection with the sockets by which the scent-scales were 

 articulated with the membrane of the wing. He thought at 

 the time that he was the first to observe this peculiar con- 

 nection of tracheae with the scent-patch, but had since found 

 that he had been anticipated by Fritz Miiller, who saw every- 

 thing. Lt.-Col. Manders had also noticed it, though his 

 observations on the point were at present unpublished. Dr. 

 Dixey went on to say that he had put forward the suggestion 

 that by the means of this tracheal supply, the products of the 

 special secreting cells which had been observed (though not in 

 actual connection with the scales of a scent-patch) by Weis- 

 mann, Giinther and others, might be propelled, as it were by 

 a vis a tergo, into the scent-scale, and so, in a volatilised 

 condition, into the outer air. In many cases of isolated 

 scent-scales furnished with a proximal disc, an evident aper- 

 ture existed in that part of the disc which was included in 

 the socket. Through this the interior of the scale might be 

 put into communication with the secretory apparatus lodged 



