260 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



to find an egg mass in which over 95 per cent of the eggs did not contain the black 

 pupae of the parasite and in most cases 99 to 100 per cent were affected. So effective 

 were the parasites that the control of the outbreak was undoubtedly due to them much 

 more than to any remedial measures. 



At about the time when the American parasite was reaching a state 

 of efficiency, a large number of eggs of the brown-tail moth contain- 

 ing the brood of one of the European species was sent to Prof. Sander- 

 son for liberation in the rose house. They were received too late for 

 service, but had they been sent at an earlier date it might easily have 

 been claimed, and with perfect confidence, that the final results were 

 the direct outcome of the colonization experiment. 



In such circumstances as these it would (or at least it seems from 

 this distance as though it would) easily be possible and practicable 

 to collect masses of the parasitized eggs and by keeping them in cold 

 storage have ready at hand within the following twelvemonth a 

 supply of the parasites which would be available should the natural 

 stock perish through lack of food, and the destructive increase of the 

 host follow. Parasitized eggs could be sent from one greenhouse to 

 another, and stock could be kept in cold- storage in one city to be 

 drawn upon by a florist in any other part of the country when need 

 arose. 



Another possible use for the parasite is as an enemy of Heliothis, 

 which is causing serious injury to tobacco in Sumatra. Dr. L. P. 

 De Bussy, biologist of the tobacco growers' experiment station at 

 Deli, has already undertaken its introduction there, and will attempt 

 to handle it after somewhat the same manner as that above described. 



TELENOMUS PHALJ1NAEUM NEES. 



A small number of this species was reared from imported eggs of 

 the brown-tail moth from several European localities in 1906, and an 

 attempt was made to secure reproduction in the laboratory. Ovi- 

 position was secured, as in the instance of similar attempts with 

 Trichogramma, but it did not result successfully, and apparently for 

 the same reason. 



In 1907 a somewhat larger number was reared, and an abundant 

 supply of suitable host eggs having been provided, this number was 

 soon increased several fold, and one large, and several smaller colonies 

 of the parasite were liberated under very satisfactory conditions late 

 in the summer. It was found that the reproduction could be secured 

 upon host eggs which had been killed through exposure to cold, and 

 the experiment was made of hibernating the brood in cold storage, 

 but without success. 



In 1908 the quantity of eggs of the brown-tail moth imported was 

 smaller than during the previous year, and only a very small propor- 

 tion of them proved to be attacked by the Telenomus. Not nearly 



