December,' 13] GLASER AND CHAPMAN: GIPSY MOTH WILT DISEASE 487 



4. Caterpillars dead from infection with the filtered virus are flaccid, 

 completely disintegrated and full of polyhedral bodies. 



5. Usually the complete absence of bacteria immediately after 

 death is very striking as cultures and smears show. 



6. Minute dancing granules were observed in the diseased tissue 

 cells with ver}' high powers. 



7. These same granules were also noticed in the Berkefeld filtrate. 



8. There is no evidence that the polyhedral ))odies are stages of the 

 filterable virus. 



9. A large number of caterpillars used in the experiments died, due 

 to disturbances in their normal physiological activities. 



10. There is no evidence that the wand is an important factor in 

 distributing the disease. 



1 1 . Infection naturally takes place through the mouth by means of 

 the food. 



12. Apparent immunity is a striking phenomenon. 



Conclusion 



In conclusion we wish to thank Professor William Morton Wheeler 

 for the interest which he showed during the progress of our experi- 

 ments. We also wish to thank Mr. A. F. Burgess, director of the 

 Gipsy Moth Laboratory at Melrose Highlands, for the kindly coopera- 

 tion which he has given us. Had he not provided efficient assistants to 

 aid in feeding and looking after the trays, it would have been impossi- 

 ble to have accomplished much. We wish further to thank Miss 

 Teresa Sheerin, one of our assistants, whose conscientious w^ork and 

 interest aided materially in our researches. Last, but not least, we 

 would like to express our thanks to all the field men w^ho assisted in 

 this work. 



BIBLIOGRAPHY 



1886. Forbes, S. A. Studies on the contagious diseases of insects. Bull, of the 

 Illinois State Laboratory of Natural History. Vol. II; pp. 257-321; figs. 2. 



1905. Sawamura, S. On the large bacillus observed in flacherie. Bull, of the 



CoUege of Agriculture. Tokyo Imperial University. Vol. VI; No. 4; 

 pp. 375-386. 



1906. Sawamura, S. Note on bacteria pathogenic to siUc-worms. Bull, of the 



College of Agriculture. Tokyo Imperial University. Vol. VII; No. 1; 



p.l- 

 1909. Wahl, Bruno. Uber die polyederkrankheit der Nonne, I {Lymantria monacha 

 L.) Centralblatt fiir das gesamte Forstwesen. Mitteilung der K. K. 

 Pflanzenschutzstation in Wien, II. Trunnerstrasse 1, pp. 1-12; fig. 2. 



1909. Reiff, W. Einige flacherie-experimente mit der "Gypsy moth" {Liparis 



dispar). Societas entomologica. Jahrg. XXIV; s. 178-181. 



1910. Wahl, Bruno. Uber die polyederkrankheit der Nonne II {Lymantria mona- 



cha L.). Centralblatt fiir das gesamte Forstwesen. Mitteilung der K. K. 

 Pflanzenschutzstation in Wien, II. Trunnerstrasse I; pp. 1-42; TafelnS. 



