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IV. Further Observations on the Structure of the Scent 

 Organs in certain male Danaine Butterflies. By 

 H. Eltringham, M.A., D.Sc, F.Z.S. 



[Read December 2nd, 1914.] 



Plates XI-XX. 



On a former occasion * I described at some length the 

 structure of the scent-glands and brushes in the Danaine 

 butterfly Amauris niavius, Linn. I am greatly indebted 

 to my friends Mr. W. A. Lamborn, Mr. J. C. Moulton, 

 Lieut.-Col. Manders, Mr. S. A. Neave, Mr. C. A. Rogers, 

 and Mr. C. A. Wiggins for further material in the form 

 of butterflies suitably preserved, enabling me to cut 

 sections and investigate the structure of similar glands 

 in other species. I am also much indebted to my friends 

 Prof. E. B. Poulton and Dr. F. A. Dixey for kindly looking 

 over the proofs of the present paper. It may be useful 

 to recall that in the case of A. niavius the scent-glands 

 were found to be located in the patch on the hind-wing 

 submedian nervure. Each gland consisted of several cells 

 communicating on the upper surface of the wing with a 

 projection which I called a " scent-cup." This structure 

 was provided with a cover pierced in the centre by a 

 minute pore. Each scent-cup was also protected by a 

 small scale, differing from the normal wing-scales in size 

 and shape. 



The two brushes situated in the hinder end of the abdo- 

 men consisted of tufts of chitinous hairs f arising from tri- 

 chogenic cells in a membranous sac, the eversion of which 

 by fluid pressure causes the extrusion of the brush. In 



* Trans. Ent. Soc. Lond., p. 399 et seq., 1913. 



f It has been pointed out to me that the insect structures com- 

 monly referred to as hairs are not hairs in the true morphological 

 sense, and of this I am, of course, aware. At the same time, when 

 speaking of hairs in connection with insects, we mean insect hairs 

 or the hair-like structures (setae, modified scales, etc.), which are 

 found on insects, and I do not think that any confusion need arise 

 on this point. 



TRANS. ENT. SOC. LOND. 1915. — PART I. (mAY) 



