186 Transactions. — Zoology. 



Art. XVIII. — Lepidoptera of Mount Ida. 



By J. H. Lewis. 

 Communicated by G. V. Hudson, F.E.S. 



[Read before the Wellington Philosophical Society, 25th September^ 



1900.'] 



The mountain-range that runs inland from the coast south 

 of Oamaru, and loses itself in the broken country behind 

 Mount St. Bathans, attains its highest altitude in Mount Ida 

 (5,600 ft.). Situated as it is in the heart of the dry belt, the 

 insect fauna of this mountain is extremely meagre, but withal 

 exhibits some peculiar features, not the least interesting of 

 which is the rapid and complete succession of species through- 

 out the summer, more especially in the Lepidoptera. 



On the shingle slopes near the summit Erebia pluto, the 

 black mountain butterfly, is common enough, and, with 

 swarms of Argyrophenga antipodum, lends an interest to the 

 otherwise dreary prospect of tussock and shingle. No 

 "Society for the Preservation of Butterflies" is needed to 

 save these two hardy little species from extinction ; they are 

 secure in the possession of country that laughs to scorn the 

 improving settler. 



Between 3,000 ft. and 4,000 ft. Notoreas insignis occurs in 

 March and April in abundance ; it is particularly attached to- 

 a species of Raoulia. Except a few " micros." and a single 

 Dasyuris hectori, I have seen no other moths on the higher 

 parts of the range. 



On the lower half, however, between 2,000 ft. and 3,500 ft., 

 many species occur. Swarms of Crambidce are out on every 

 hot day, and, of the twenty species that I took last summer, 

 no particular one had exclusive possession of the field, as is- 

 so often the case in other parts of the colony. Crambus cor- 

 ruptees may be excepted, but only in the very early spring. 

 Of the rarer Crambidce, I have taken Thinasotia claviferella 

 commonly in March amongst sedge, while Crambus flexuo- 

 sellus is a rarity represented by one specimen. On the 

 Maniototo Plains, 1,000 ft. lower, jlexuosellus is common 

 enough. Chrysophanus boldcnarum and Lythria euclidiata 

 occur all through the summer in swarms, as well as a duller 

 Geometrid, apparently new, which has the same habits as 

 euclidiata. 



The succession of species in the Geometridce is somewhat 

 marked on the lower levels, though not so noticeable as with 

 the Noctuidce. Theoxena scissaria shows first ; indeed, my 



