PLUME MOTHS OF CEYLON. 9 



STEGANODACTYLA, Wlsm. 



Steganodactyla concurs a, Wlsm. 

 Wl5iw., E. M. M., 1891, 241 ; Novitates Lepidopt., t. xii., f. 3. 



Distribution. — Colombo, Galle, Weligama, Kandy, Pundalu-oya, 

 Madulsima, Diyatalawa, Haputale. Ou£o<k o£ &»U Mr K*, W <ue*MZ 



Early Stages. — The larva feeds between the young unexpanded yv " 

 leaves of a common climbing Argyreia and also of Ipomcea populi- 

 folia, eating the" upper cuticular surface of the leaf into tell-tale 

 patches. 



The full-grown larva may be described as stout, rather flattened. 

 Head pale yellow. Other segments a pale grayish-green, interstices 

 of segments (only visible when expanded) darker green. Dorsal 

 surface pale ; warts with a little orange-yellow about their bases, 

 often forming a distinct orange-yellow or reddish median stripe. 

 An ill-defined broad dark lateral shade appears to be caused by 

 the contents of the alimentary canal, as it disappears towards the 

 anal extremity when frass is voided. Hairs white, usually very 

 conspicuous. (Plate E, figure 1.) 



In confinement the larva generally wanders off the food plant to 

 pupate, but occasionally attaches itself to the upper surface of the 

 midrib of a leaf. I have never found the pupa in nature. 



The pupa is usually suspended horizontally to a vertical support, 

 being closely appressed ventrally to the resting-surface by the 

 double set of cremastral hooks. Its colour, which is variable, is 

 some shade of pale green, but it always has a broad reddish medio- 

 dorsal stripe. These colours fade into a greenish-brown shortly 

 before emergence, which takes place after about six days, the 

 moth generally appearing in the late evening, quite contrary to the 

 ordinary habits of plume moths. The pupa is comparatively 

 extremely small, and it seems marvellous how such a large moth 

 can emerge from a pupa-case which does not seem sufficiently large 

 to contain its abdomen alone. (Plate E, figure 2.) 



"Habits. — Although the larvae are common and easy to find and 

 rear up, the moth itself appears to be of a very retiring nature and 

 is rarely seen in a wild state, although it occasionally comes into 

 light. It is very difficult to beat from the food plant and, when it 

 is disturbed, the flight is rapid and the moth easily overlooked. - 



Observation. — It is noteworthy that up-country specimens — i.e., 

 from Kandy and above — are distinctly larger than those from the 

 coast districts, the former having an average expanse of about 

 16-17 mm. as against about 12-13 mm. in the case of the latter. 

 It may be permissible to conjecture that this difference is due directly 

 to climate, the up-country specimens having had longer-feeding 

 larva? which, as a rule, produce larger imagines than larvae which 

 feed for a shorter period of time ; but, of course, this is one of the 

 innumerable problems in Sinhalese entomology in which we require 

 c 7(6)09 



