POLYPTYCHUS. 167 



Habits. — Food-plants : Ehretia l&vis Roxb. and Cordia 

 obliqua Willd., both of the family Boraginea?. The larva eats 

 the egg-shell on hatching and then rests, without eating any 

 of the food-plant, until after it has made the first moult. 

 This habit of eating nothing but the egg-shell till after the 

 first moult is peculiar to this genus and to a few other genera 

 of Hawk-Moths, and is not often noticed among other lepi- 

 dopterous insects. It will be noted that the larvae which 

 have this habit have round heads in the first instar, as is the 

 case with all sphingid larva?, the head becoming triangular 

 at the first moult. The larva, when small, lies stretched 

 straight along the midrib or a vein on the underside of a leaf ; 

 when alarmed it turns the head to one side till it touches the 

 middle of the body. In later instars it lies along the midrib 

 of a leaf, with the head and anterior segments raised slightly 

 from the surface, the head held so that the long processes lie 

 parallel with the surface. In the last instar the larva adopts 

 the typical sphinx attitude. Pupation takes place in a cell 

 underground. The moth is seldom attracted by light, and we 

 have not seen it feeding. Bred $ $ do not attract wild <§<§ 

 readily, and we have only once succeeded in getting a bred pair 

 to mate. 



In a batch of moths bred from the egg the history was as 

 follows : — Larva? hatched five days after eggs were laid ; 

 larval growth with five (or sometimes six) moults, about 

 thirty days ; pupal stage about eighteen days. 



37 c. Polyptychus trilineatus trilineatus Moore. 



Polyptychus trilineatus, Moore, 1888, p. 390 (Dharmsala, $) ;. 



Butler. 1889, p. 25, pi. cxxi, fig. 4. 

 Polijptyclms trilineatus trilineatus, Roths. & Jord., 1903, p. 238 : 



Jordan, 1911, p. 240 ; Seitz, 1925, p. 537. 

 Polyptychus dentatus, Hampson (non Cram.), 1892, p. 69. 



Imago. — The type-specimen, a $, is an aberrant individual. 

 In a <$ bred by us the colour agrees closely with P. dentatus. 

 being pale with a grey bloom, paler than P. t. undatus, but the 

 lines of the fore wing are in the same position as in the other 

 subspecies of trilineatus ; dentate line between the two outer 

 lines of fore wing upperside obscure or absent. Expanse : 

 S 74-102 mm., $90-112 mm. 



$. The two apical teeth of harpe close together, the ventral 

 tooth but slightly longer than the upper one. The fish-tail 

 process and the lateral processes of penis-funnel as in undatus y 

 the right prong of fish-tail longer than left one, as is also the 

 case in undatus. 



Hab. W. Himalayas (Dharmsala; Dehra Dun). Very rare, 

 few specimens in museums. We have bred a few from larva? 

 found in the Siwalik Mountains near Dehra Dun, in forests 

 with heavy rainfall at an elevation of about 2,500 feet. 



