6 MB. GUY A. K, MARSHALL ON THE [Jan. 19, 



probably largely influenced by the surroundings, such as soil, leaves, 

 &c., in which the insect habitually rests. 



In addition to these there are instances in which a species 

 may show seasonal modifications peculiar to itself. For example, 

 in T. pleione, Ivlug, the area of the diseal yellow is reduced in the 

 dry season, which, however, does not occur in its near allies. 

 Again, T. hetaera, Gerst., exhibits a marked reduction of the crimson 

 apical patch ; whereas in the dry-season form of T. re(jina, Trim., 

 the purple patch is, if anything, rather larger and brighter, owing 

 to the reduction of its black borders. 



With regard to the nomenclature adopted in this paper, my 

 object has only been to give a more or less clear definition of the 

 species which constitute the genus Teraeolus, and T have not 

 attempted in any way to apply a system of nomenclature to the 

 variations, whether local or otherwise, to which these species may 

 give rise. Besides, at the present time the classification of such 

 variations is in a somewhat chaotic state, at least so far as exotic 

 Lepidoptera are concerned, and the same form may be referred to 

 by various authors either as a true species, subspecies, local race, 

 climatic variation, variety, or seasonal form. This is, no doubt, 

 due to the lack of any standard definition, so that each man is a 

 law unto himself in the matter. However, there is no doubt that 

 it will be necessary to apply names to a few of the more marked 

 local forms, which I regard as incipient species ; and in such cases 

 the trinomial system of nomenclature seems to me to be the 

 clearest and most satisfactory, as we thus keep in view the gradual 

 evolution of the parent species. But at the same time I cannot 

 inveigh too strongly against the idea that every slight deviation 

 from the typical colouring of a species must be encumbered with 

 a Latin name, which appears to me to be thoroughly pernicious, 

 and stultifies the very object of nomenclature, which is to elucidate 

 and not to confuse. This variety-mougering has reached such a 

 pitch in Europe that even artificial vai'ieties are adorned with 

 " scientific " names, which has certainly not been done in the 

 interests of science, but is due partly to a misguided ambition on 

 the part of the gentlemen who coin the names, and partly to trade 

 motives. With i*egard to the naming of seasonal forms, I can see 

 no more necessity for it than for the naming of sexual forms ; and 

 a simple solution of the difficulty would be the adoption of three 

 standard signs or letters, to signify wet, dry, and intermediate 

 forms respectively, in the same way that signs are used to dis- 

 tinguish the sexes. 



1. Tebacolus subfasciatcs. 



Teraeolus siibfascialus, Swainsou, Zool. 111., Ins. ii. pi. 115 

 (1823). 



Ptifchopterifx hohemani, Walleugren, K. Sv. Vet.-Akad. Handl. ; 

 Lep.'Ehop. Caf. p. 18 (1857). 



On the eastern side of South Africa this swift-flying Teraeolus 



