( Iv) 

 it is not scaled, is covered witli I'iliae, only the parts near the joints and 

 close to the dorsal scaling being in many cases naked or sparsely ciliated. 

 Pageustecher * calls tlie antennae of CuIlithilidK,' "naked,"' and Hampson t 

 describes those of Ai/nri.sfidat' as being " not ciliated." Both authors are 

 wrong, the antennae of Cdllldiilidne and of Agaris'ithte being scaled above 

 and ciliated below. There is no antenna among Lepidoptera which is not 

 ciliated, and the term " naked " can with some justitication only be emplo3-ed 

 for antennae which are not scaled, and therefore have a naked dorsal surface 

 (apart from some bristles and setiferous jiits). The evenly ciliated ventral surface 

 as we find it in Rhopalocera among the Lijcrieniilae and Ili:-<pcrn(fac, and in 

 great abundance among the Heterocera, more especially in the female se.\, far 

 less often in the male sex, represents a generalised state of development from 

 which a variety of specialisations have started, which, tliongh resulting in 

 widely different structures, have nevertheless all the same tendency — namelv, 

 to make the antenna more efficient as an organ of sense. This is accomplished 

 by enlargement of the area bearing the sensory organs — i.e. by the increase in 

 their number — or by concentration of the organs, or by enlargement of the 

 organs themselves, these modifications obtaining either singly or together. The 

 concentration of the ciliated area into such well-circumscribed grooves as are 

 described and figured in Nov. ZooL. vi. p. 374. t. 14. 15, does not occur among 

 the Heterocera. The enlargement of the distal part of the antenna into a 

 club, which is normal for Rhopalocera, among which non-clubbed antennae are 

 extremely rare {Pseuchpontia^, is met with in a number of Heterocerous families, 

 such as Gastniidae, Aegeriidae, Sphingidae, Zijgaenidae, Agarisfidae, Callidu- 

 lidae, and also among Geometridae and Noctuidae. As regards mere outline 

 the clubbed antennae of rej)resentatives of different families are sometimes not 

 distinguishable. The Australian Castniufuf, which appear to form a different 

 subfamily from the Neotropical species of that family, resemble in the short 

 and abrupt club certain I'ieridae, and some Hesperildae and Neotropical 

 Ca.sfniidae have practically the same antennal outline as some Sp/ungidae. The 

 most strongly clubbed antenna of Sphingidae we find in Ilacmorrliagia and 

 Rkopalop«>/chc ; from these to the setiform antenna of Megaconiia there occur 

 all intergradations in shape. It is by no means only the ciliated surfiice which 

 becomes expanded in the clubbed antennae of Spliingidat\ The dorsal area is 

 often projiortionally more enlarged than the ventral area. This can best be seen 

 in a frontal view of a segment of the club of Ccpkonodes or Haemorrhagia, 

 where the axis of the club will be found further ventral than in a segment 

 from the middle of the antenna. By axis we mean an imaginary hollow 

 cylinder of the width of the joints.^ There is no real axis, each segment 

 representing, so to sjicak, a box with an opening each at the proximal and 

 distal sides. The edge of this ojiening is more or less raised and joined to the 

 edge of the opening of the next segment. The diameter of the cavity of the 



* TierreicU xvii. (If02). j Lepid. Phalatnae iii. p. r.l5 (1901). 



X Joint and segment should not be confounded, 



