252 E. P. Stebbing — Life-history of Arbela tetraonis. [No. 4, 



On the life-history of Arbela tetraonis, Moore, a destructive Insect pest 

 in Gasuarina Plantations in Madras. — By E. P. Stebbing. 



[Received July 25th. Read August 5th, 1903.] 



How little is really known about our Insect foes in India is becom- 

 ing increasingly evident day by day. An insect suddenly swarms over 

 an area in numbers owing to some particularly favourable conditions in 

 its surroundings, it commits serious depredations in the fields, orchards, 

 or forests of the tract it is invading, and owing to its being so very much 

 en e'vidence or owing to the great damage it is committing specimens are 

 collected and sent for identification to specialists. The odds are greatly in 

 favour of its being new to science. Instances of this state of affairs are 

 numerous, and it may be said that leaving out of account the butterflies 

 and one or two other groups which have received attention it is easier 

 to pick up a new species in many parts of the country than to collect one 

 that is known. The insect about whose life-history, as far as it is at 

 present known, I wish here to put on record a few notes furnishes an 

 illustration of the aptness of the above remarks, since although rare in 

 Collections and new to those of the Indian Museum its larva has been 

 known for some years as a destructive bark eater in Casuarina planta- 

 tions on the eastern seaboard of Madras. There may, however, be said to 

 be some excuse for its having remained so long undiscovered since it be- 

 longs to a family of moths, closely allied to the] Cossidse, which have 

 been little studied and the life histories of whose members are little known > 

 the larva3 living mostly in the wood of trees. The moths are rarely 

 seen and owing to the habits of the larva are difficult to find. The pupal 

 stage and pupa of the English Goat-moth is known, and has been 

 described j but very little is known as to other pupa3 of the family. The 

 description of the pupal stage of this insect given below is therefore 

 of some interest. 



In the Indian Museum we have but 4 genera aud 11 species of the 

 family Oossidse from the Indian Region, the insects being Cossus cadambe i 

 Duomitus cer amicus, D. strix, D. lenconotus, D. mineus, Azygophleps asylas 

 (said to be S. African by Hampson in the Fauna), A. pusilla, Zeuzera 

 indica, Z. pyrina, Z. multistrigata, and Z. Qoffese. There are also two un- 

 named specimens one of which is an Arbela and closely allied to the 

 insect under description. This latter specimen was obtained by the late 



