340 



aware, is there any special distribution of air-tubes to the scent- 

 patches. But in several other Pierine genera, e.g. Catopsilia, 

 Colins, Tcracolus, the specialised patches, when present, are 

 provided with a plentiful supply of ramifying " tracheae," some- 

 what similar to those described and figured by Fritz Müller 

 m the Satyrine butterfly Antiryhœa archcea Hübn. In Teracolns 

 fausta Oliv, the male is furnished on the lower surface of the 

 forewing with a well-defined scent-patch. This is pervaded 

 by numerous tracheae which, starting at right angles from the 

 submedian vein, run roughly parallel to one another through 

 the patch, giving oft" numerous fine ramifying branches. These 

 latter form a reticulum with hexagonal meshes, the interstices 

 of which appear to correspond with the sockets for the insertion 

 of the specialised scent-scales, there being usually one such 

 socket to each interspace. Besides this reticular structure, 

 still finer ramifications are visible, some of which in a few in- 

 stances seem to end in connection with the proximal extremities 

 of the scale-sockets. 



In Catopsilia florella Fabr. the scent-patch on the upper 

 side of the hindwing is well furnished with tracheal branches, 

 the general arrangement of which is not unlike that in Tcracolus 

 fausta. The main tracheal branches run forward from the 

 subcostal nervure in a row like the teeth of a comb, traversing 

 the scent-patch, and becoming lost to view immediately beyond 

 it. Each socket belonging to a specialised scent-scale occupies 

 a definite area of the wing-membrane ; these areas appear to 

 correspond with the hexagonal reticulum in T . fausta, but the 

 connection with tracheal ramifications is less evident, and the 

 areas have a rounded rather than a hexagonal contour. Their 

 appearance in a patch denuded of scales is very suggestive 

 of the acini of a racemose gland. A similar arrangement is 

 visible in the corresponding scent-patch of Catopsilia pyranthe 

 Linn. 



On the underside of the forewing in C. florella, the specialised 

 scales take the form of long hairs which are collected into a 

 flattened fringe or tuft Iving along the inner margin of the wing, 

 and covering the scent-patch of the hindwing in the ordinary 

 position of rest. The region of the wdng occupied by these 

 hairs is also well supplied with tracheal branches, whose 



