DISTRIBUTION OF PAPILIONIDiE IN THE HIMALAYAS. 199 



Himalayas are situated wholly outside the astronomical limits of 

 the Tropics (being between 27° 5' and 28° 10' north latitude), by 

 reason of its sheltered position, equable temperature and super- 

 abundant precipitation, the tropical zone is powerfully repre- 

 sented in its animal and plant-life, which extends from the 

 malarial Terai Jungle and Sal Forest at the foot of the outer 

 hills at the low altitude of only about 200 ft. above the sea-level 

 to 2500 ft. or thereabouts. To this circumscribed belt the most 

 strictly tropical species of butterflies are chiefly confined. Among 

 the Papilionidae, which are specially characteristic of this zone, 

 special mention may be made of the following i — Ornithoptera 

 rhadamanthus, Pangerana didoneus, Tamcra castor, Menamopsis 

 slateri, M. epycides, Isamiopsis teleachus, Paranticopsis megarus, 

 P. xenocles, P. macareus, Pazala glycerion, Pathysa agetcs, P. 

 antiphates, P. anticrates, Zetides eurypylus, Z. hathycles, Mean- 

 drusa evan. While the following, although they belong more 

 properly to the fauna of the peninsula, may also be enume- 

 rated, namely : — Mcnelaides aristolochice, Iliades polymnestor, 

 Lartias p)olytrs, Orpheides erichthonius, Pathysa nomius, the 

 second and fifth of which are only occasional stragglers from 

 the plains, and have not been known to perform their metamor- 

 phoses within the district under discussion. 



Most of the typical forms of arborescent vegetation extend 

 upwards to 5000 ft. or thereabouts, which may be taken to be 

 the upper limits of the subtropical zone, between which and the 

 one below there is apparently not a great deal of difference 

 either in the zoological or the botanical physiognomy, so that 

 the fauna and flora are in reality only an extension of the pre- 

 ceding, the principal difference consisting in the gradual elimina- 

 tion of the strictly tropical element towards the confines of the 

 belt above. The majority of the intertropical species of butter- 

 flies ascend to various altitudes within this zone, for the most 

 part, however, performing their transformations probably below 

 4000 ft., though in the imago state some of them may occasion- 

 ally be seen considerably higher up the mountain sides, while 

 towards the upper limits an entirely new element commences to 

 come into existence in the shape of temperate modifications of a 

 tropical fauna. 



Between 5000 ft. and 7500 ft. or so the warm-temperate zone 

 holds sway with its sombre, dense forests of dark olive-green 

 oaks and chestnuts and thick undergrowth of laurels and ferns. 

 It is here that some of the most interesting Himalayan Papi- 

 lionidfe have their headquarters, the various species which are 

 endemic or nearly so to this particular climatal belt consisting 

 exclusively of temperate modifications of tropical forms belong- 

 ing to the Indo- Malayan fauna, corresponding to those occurring 

 in the more elevated districts of Southern China, most of them, 

 indeed, being absolutely identical therewith. The following is a 



