Structure of Scent Organs in Male Danaine Butterflies. 173 



structure, though the hairs are far more irregular in trans- 

 verse section. Whether owing to actual divergence in 

 structure or to some difference in the condition of the 

 specimen or method of preparation, the hairs in longi- 

 tudinal view seem to show their structure more distinctly 

 than in T. rnulciher. Over a large part of their length 

 they are covered with projections, the form of which I 

 have endeavoured to show in PL XX, fig. 35. There is no 

 dust-apparatus and no accessory vesicle attached to the 

 brush-bag. 



Hestia lynceus, Drury. 



The species of the genus Hestia do not possess either 

 scent-patch or pocket on the wings. They are, however, 

 remarkable in having four abdominal brushes instead of 

 two. Whilst the purpose of this modification is obscure, 

 its origin is at least suggested by the condition of the 

 brushes in such a species as Amauris niavius, where a 

 separate tuft of stiff black hairs arises from a limited area 

 of the brush-bag. The auxiliary brush in Hestia seems 

 to represent a modification of this special tuft lying in a 

 separate bag. It lies parallel with the main brush and 

 rather above it. It is much shorter and more slender, the 

 basal end being less deeply placed in the abdomen. It is 

 of simple structure, contains but one kind of hair, and the 

 containing bag appears to have a slightly glandular struc- 

 ture confined to one side. PL XVII, fig. 2, shows a section 

 of one of these brushes beyond the glandular level of the 

 bag. Near their origin the hairs are occasionally in- 

 vaginated along one side, giving the section a reniform 

 appearance. Under a high power the hairs present a 

 close resemblance to those of the larger brush in the same 

 species. PL XVII, fig. 3, shows a section of the large brush, 

 close to the basal end. It will be observed that the brush- 

 bag is formed of a mass of small cells, differing entirely in 

 appearance from those found in the same situation in 

 species of Amauris, but resembling the glandular cells in 

 the brush-bag of T. rnulciher. PL XVII, fig. 4, is a section 

 taken rather further from the base, and shows much the 

 same structure, which continues for some distance (fig. 5). 

 Finally, the glandular structure disappears and the bag 

 towards its mouth becomes a mere membrane (fig. 6). 



The hairs of which the brush is composed, though well 

 rounded at their origin, become somewhat flattened and 



