1902.] H. H. ULnim—Life-History of Helopeltis theivora. 133 



XII. — Note on a disputed point in the Life- History of Helopellis theivora. 



— By Harold H. Mann, B.Sc. 



[Eeceived April 30th ; Read May 7th, 1902.] 



As is well known, Helopellis theivora, — the " Tea Bug of Assam " as 

 it was called by Mr. Wood-Mason, the " Mosquito Blight" as it is gen- 

 erally termed — is the most alarming pest which has yet appeared on tea 

 cultivated in India. It causes the more disquietude as it tends to 

 increase as years go by, — fluctuating according to season, but generally 

 increasing, and invading new areas. During 1901, which was a parti- 

 cularly bad year in almost all districts subject to the pest, a very 

 moderate estimate gives seven lakhs of rupees as the nett loss to the 

 Indian Tea Industry from this cause alone. 



Though we have a knowledge, thanks to Peal,* Wood-Mason,f Dud- 

 geon, { Watt§ and Green,^* of the general life-history of the insect from 

 the egg to the adult stage, yet there remain several points which have 

 been very obscure. Of these the most important is the question as to 

 what becomes of the insect during the time when it apparently dis- 

 appears from the tea bush. So complete is this disappearance, as a rule, 

 that most planters living in affected districts in North-East India have 

 hardly ever seen a single insect during January, February and March. 

 Mr. Dudgeon has suggested that it hibernates in the ground, but offers 

 no evidence for his position, and declares frankly that he had not been 

 able to verify his conjecture. It has also been supposed that hiber- 

 nation takes place in water and swamps, but again, not a scrap of 

 evidence in favour of the view exists, and the same may be said of the 

 veiy general idea among tea planters that in the cold weather the 

 Helopeltis goes on to various jungle trees. 



With a view of acquiring information on this point, I have spent 

 a considerable time in January, February and March of the present year 

 in two of the districts most affected by the pest — the Darjeeling-Terai, 

 and Cachar — at a period when the insect was supposed to be hibernating. 

 As a result I have come to conclusions of which the following is 

 a summary. 



The Helopeltis theivora can be found on the tea bush in every stas^e 

 of development during every period of the year. The cold weather 



* Tea Cyclopedia, 1881. 



t The Tea Bug of Assam, 1884. 



J Indian Museum Notes. Vol. Ill pp. 33-38. 



§ The Pests and Blights of the Tea Plant 1898. 



IT Royal Botanic Gardens, Ceylon. Circular, No. 21 (1st Series), 1901. 



