TWO NOTORIOUS INSECT PESTS. 693 



VI. Hibernation. 



A. P, machoeralis — 



54. The insect hibernates in the larval stage. Hibernation commences 

 about the beginning of November and lasts about 22 weeks. When 

 about to hibernate, the larvae leave the trees on which they have been 

 feeding and construct cocoons, in which the hibernating stage is passed, 

 usually, if not always, in the ground. The hibernating larvae are often 

 found in clusters under large stones, and where there are no stones I 

 have found them at a depth of several inches in the ground. 



At the end of the hibernating stage, pupation takes place inside the 

 cocoon, the pupal stage occupying the usual period of about 7 days, and 

 the moth appears in April. 



B. H. puera — 



55. I was unfortunately not able to discover how or where the insect 

 hibernates, but it is probable that it hibernates in the larval stage in the 

 ground. This, however, of course requires confirmation. 



VII. Number of Generations in the Year. 



56. In the case of both species the first severe larval attack of the 

 year noticed by me was in June-July, and the larvae leave the trees 

 about November. During this period one generation succeeds another 

 without intermission, providing only that there is a sufficient food supply 

 for the larvae, the number of generations passed through being four to 

 five. In Madras and Burma severe larval attacks have been reported 

 as early as April, and here the number of generations passed through 

 in one year appear to be seven. 



57. I have already mentioned in para. 18 above that, in the case of 

 Pyrausta, the first moth among those bred by me appeared, at the 

 close of the hibernating stage, on April 7th. Allowing a month for 

 one complete life cycle, we should expect the moths of the first com- 

 pleted generation of the year to appear on May 7th, which practically 

 agrees with what has been recorded regarding the first appearance of 

 the larvae in Burma, for Major Bingham has noted* that he collected 

 larvae towards the end of April 1892 in the Eangoon Division, from 

 which the first moths were obtained on May 6th. In the case of the 

 dry teak forests of the Central Provinces, however, the larval attacks do 

 not commence in April, for the simple reason that the teak trees are 

 then leafless, the full foliage not appearing until June-July. During 

 the period April-June, therefore, a few larvae may survive on the trees 



* See Indian Museum Notes, Vol . Ill, No. 2, p, 93, 



