THE ANTENNiC OF LEPIDOPTERA. 227 



Bodine describes a patch of extremely long, but little specialised, 

 scales on the dorsal surface of the scape. These sometimes form 

 striking tufts. On the clavola the scales are more specialised, and in 

 moths, for the most part, are arranged on the dorsal surface in two 

 transverse bands. The antennal pectinations also, in some species, 

 bear scales. " Even in those antennaj which are scaled apparently 

 over their whole surface, there is a comparatively free space on the 

 ventral and more highly specialised face " (Bodine). 



There are, at least, six kinds of antennal organs which are in 

 communication with nerves, and are, therefore, presumably organs of 

 special sense. These are : — 



(1) Short, slender, pointed sense-hairs, hollow, but closed at the 

 free end. They are attached to the chitinous ring at the end of a pore 

 canal, and are usually more or less flexible. From the interior a nerve 

 fibre (from the antennal nerve) enters the cavity of the hair. This 

 type of sense-hair is found very generally in Lepidoptera (Jugate, 

 Frenat.e and butterflies) (PI. II., fig. 3). 



(2) Long, and very stout rigid bristles, closed at the end, easily 

 recognised by their thick base and tapering form. They vary greatly 

 in size, and more than one nerve-cell is in connection with this kind of 

 sense-hair. There are but few found on a single segment (PI. II., fig. 4). 



(3) Long, stout stift' hairs, hollow and closed at free end. It is 

 very like the first type, but the nerve cell is smaller, and the hair is 

 more firmly attached. Their distribution is limited, and they are said 

 not to occur in the JuoATiE, Hespekides and Papilionides (PL II., fig. 5). 



(4) Pits or depressions, guarded at the opening by stiff projections 

 of chitin, and containing single rods or cones, connected with nerves 

 from the interior (PI. II., fig. 6). Sometimes two or three pits grow 

 together. Among the butterflies they are much deeper. In Pyramci^ 

 canhd there is a circle of stift' points around the base of the cone. A 

 similar circle is described in Vanessa io by Hauser. These pits are found 

 usually on the ventral surfaces of the shaft and pectinations, 

 whilst in the butterflies they are most numerous on the club, but 

 sometimes extend to the other segments. 



(5) Short conical projections, which have become so thick as to 

 lose their character of hairs, and, in a manner, resemble an everted 

 pit (4), the nerve apparatus being similar to that described under the 

 first type of sense-hair, and like that which supplies the pits. The 

 apex varies — blunt, pointed, hollowed, etc. These sense-cones are 

 found in all the B'renat.i:, but not in butterflies, nor in the Jugate. 



(6) Another set of nervous apparatus is always situated in the 

 pedicel. It consists of a number of nervous rods, which are gathered into 

 small conical bundles, and terminate within pores situated in the 

 membranous ring which connects the chitinised walls of the pedicel 

 and the proximal joint of the clavola. It will be at once evident that 

 any movement of the clavola upon its base, whether caused by contact 

 or vibration, would be at once felt in the membrane in which these 

 rods lie. As there are rods in every part of this membrane, a 

 definite impression of the movement would be produced in the sense- 

 rods. 



The presence of so many nervous structures in the antennae leaves 

 no doubt that these organs are the seat of more than one special 

 sense. Difi'erent as must be the range of perception in insects. 



