312 
LETHE. By H. Frtthstorfer. 
sidonis. 
gclduba. 
vaivarta. 
nicetellci. 
siderea. 
cannot be used for the but otherwise affords a safe guide. A reliable indication is furnished by the shape 
of the wings, whether rounded or with tail-appendages, the more or less pronounced swelling of the costal 
vein and not least by the fact that in whole series of species the loAver discocellular of the hindwing does 
not touch the furcation of the upper and middle median, but the upper median vein, which is then separa¬ 
ted by a broad, stalk from the middle median. But all the members of the Lethe group in common have the 
costal and subcostal of the fore wing coincident for half their length. The secondary sexual characters are 
very various; they may be present on both wings or only on the fore- or only on the hindwing. But in no 
species have hair-pencils yet been detected., which play so essential a part in the grouping of the Mycale- 
sids, never even tufts of long hairs. The clasping-organs are sharply differentiated in the separate groups, 
thus in true Lethe , as in Melanitis, the lateral clasps of the uncus are apparently absent, whilst in Hermias 
they are not only distinctly present, but also bear a very broad, horn-shaped point. The valve may be 
narrow and very long and simple (Lethe) or short and. with dorsal protuberances (Hermias). Larva and pupa 
are described in vol. I (p. 82); they are only known of about four species, notwithstanding the accessibility 
of their food-plants — bamboos and other grasses. As a rule they are mountain butterflies and the traveller 
encounters one species — L. rohria — as a living altimeter in the Sunda Islands when he approaches 1200 m., 
as it never descends lower, but immediately appears where the cool mountain breeze begins to be felt. All 
the other species love the shade and are most lively at early morning or in the evening twilight. The butter¬ 
flies rest with folded, wings in the bamboo thickets or on blades of grass, but rarely, like Mycalesis, on 
the ground. The head-quarters of the genus is continental. Nearly 50 species of the Lethe group are found 
within the limits of the Indian Empire, but Borneo and Java have seven, Lombok three, Celebes and the 
Moluccas only one species. The genus has not reached the Papuan region and Australia in its eastward course. 
Altitudes of 2—3000 m. suit them best, only one species ascends to 14 000 ft. ( maitrya ). According to my ob¬ 
servations in Hong-Kong one species (arete) smells extremely strongly of vanilla. 
Group Sinchula Moore. 
The most insignificant forms of the genus. Hind wing rounded, without distinct point at the lower median. 
The lower discocellular does not touch the fork of the upper and middle median, but arises distally to it. Costal dis¬ 
tinctly cystose. <J without sexual spot on the upper surface. 
L. sidonis Hew. (vol. I, p. 85, pi. 31 d upper surface and vol. IX, pi. 97 c under surface) breaks 
up into two seasonal forms, of which Hewitson knew and described that of the wet season (97 c), of which 
we reproduce the under surface. The dry-season generation gelduba form. nov. is as usual smaller and is 
above paler with brighter bronzy sheen. The anterior ocelli of the hindwing beneath are partially suppressed, 
whilst the posterior are reduced. Likewise the grey-blue median stripes are frequently absent, particularly in 
Bhotan examples. In Assam occurs a local form, which is larger and beneath more brightly coloured. Accord¬ 
ing to Elwes sidonis is one of the commonest Lethe of Sikkim, where it occurs in the forest zone from 4—8000 
ft. from April to November, especially on the paths, and either remains on the ground or on lower vege¬ 
tation. Sikkim, Bhotan; Assam. 
L. vaivarta Doh. nearly approaches the preceding and might be regarded as a western race of sidonis 
if Doherty had. not stated, that the clasping-organs are different. Judging from Moore’s figure of the typical 
specimens the most essential distinguishing character consists in the longitudinal bands of the forewing be¬ 
neath being broader and yellow instead of violet and the eye-spots of the hindwing larger and showing through 
above. The dry-season form was discovered by Doherty in the Kumaon Himalayas, but the species ex¬ 
tends further to the west; for it is also recorded from Kangra, in southern Kashmir. Larva light green with 
two horns on the head and pale longitudinal and. transverse stripes. It lives on the mountain bamboo Arun- 
dinaria falcata Nees. Pupa green, more rarely red-brown, short, with two tubercles on the head and whitish 
sides and whitish speckles on the ventral side. 
L. nicetella Nicev. (97 c). Upper surface unicolorous black-brown with slight bronzy reflection, hind¬ 
wing with the eye-spots of the under surface showing through. In the dry-season form some of the ocelli on 
the underside of the hindwing are blind and the forewing shows grey-yellow patches in the distal part. In 
July-August at Tunglo from 7 to about 9000 ft. on shady or wet places, sometimes in thousands. The 
however, is very rare. Not yet observed outside of Sikkim. 
L. siderea Marsh, (vol. I, p. 85) is a rare Sikkim butterfly, only once taken in the interior of the 
country at 7000 ft. in the rainy season. $ still unknown. Under surface of the hindwing very near to ni¬ 
cetella , but with longer stripes and the ocelli with brighter orange-coloured bordering. According to Leech 
also found as a rarity in West China. 
