244 MESSRS. MOORE, WALKER, AND SMITH [Mar. 7, 



organ cannot be used as generic characters. Thus, whenever in a 

 group of reptiles the limbs are in a more or less rudimentary con- 

 dition, the number of toes indicates only specific distinctness, and 

 sometimes it is evidently subject to even individual variation. Fur- 

 ther, the genera Seps, Gongylus, and Heteromeles had been distin- 

 guished only by the differences in the number of toes of their rudi- 

 mentary limbs, as we cannot take into account the more or less 

 complete scaly covering of the external ear-opening, which is some- 

 times very distinct, sometimes rather iudistinct, and sometimes 

 entirely hidden by an overlapping scale. At present, we know the 

 following modifications intermediate between the toeless Seps mono- 

 dactylus and the five-toed Gongylus ocellatus : — 



Fore toea. Hind toes. 



Gongylus ocellatus 5 5 (well developed). 



Gongylus capensis 5 5 (feeble). 



Gongylus viridanus 4 4 



Seps tridactylus . . . 3 3 



Heteromeles mauritanicus 2 3 



Seps monodactylus 



Consequently I am inclined to unite the species mentioned into 

 one genus, for which the name Seps may be retained. 



Several instances have been made known of animals restricted in 

 their habitat to islands, and having the organs of locomotion in a 

 much less developed state than nearly allied species of continental 

 faunas. Speculation has seized upon these instances to connect this 

 peculiarity of structure with the fact of insulation ; and the short- 

 limbed Gongylus viridanus of Teneriffe, when compared with the 

 continental five-toed Gongylus ocellatus, would appear to offer an- 

 other instance leading to the same way of reasoning. But then we 

 find that Gongylus ocellatus is also an inhabitant of Malta, Madeira, 

 and other small islands, without showing signs of imperfectly deve- 

 loped limbs, and, again, that Seps monodactylus and Heteromeles are 

 not less continental species than Seps tridactylus, as also that the five- 

 toed Sphenops sepoides and the short-limbed Sphenops meridionalis 

 are widely spread over large districts of the same continent. 



3. Descriptions of some new Insects collected by Dr. Ander- 

 son during the Expedition to Yunan. By Frederic 

 Moore, Francis Walker, and Frederick Smith. 



[Eeceived February 21, 1871.] 



(Plate XVIII.) 

 Order LEPIDOPTERA. 

 Heterocera. 

 1. Syntomis andersoni, Moore, n. sp. (Plate XVIII. fig. 1.) 



Male and female. Wings hyaline, veins bluish black ; body black, 

 with orange-yellow bands : fore wing with the costa and exterior and 



