128 GYPSY AND BKOWN-TAIL MOTHS. [Jan. 



the season was so far advanced that but few experiments 

 could be made. 



Dr. Stone's report, which also includes the results of cer- 

 tain laboratory experiments by Mr. O. L. Clark, is printed 

 in full herewith : 



REPORT ON SOME FUNGOUS PARASITES OF THE BROWN-TAIL MOTH. 



About the middle of June there was discovered at Wakefield by 

 Field Agent J. W. Enwright some pupae and caterpillars of the 

 brown-tail moth, covered with a whitish growth which appeared to 

 cause many of them to become sickly and die. Casual observa- 

 tions made by Mr. Euwright and others led them to surmise that 

 the whitish growth causing this injury was of a fungous nature. 



At the request of Superintendent A. H. Kirkland, I visited 

 Wakefield June 27, 1905, and spent one day looking over the 

 region about Wakefield in company with Mr. F. H. Mosher, labora- 

 tory assistant, and made notes in regard to the nature and extent 

 of this injury. At that time the region of fungous infection ap- 

 peared in its worst form to centre about Wakefield, with more or 

 less evidence of its occurring in Reading, Melrose and Maiden ; 

 shortly afterwards, however, it was noted quite abundantly at Mai- 

 den, Revere, Medford, etc. Mr. Enwright first noted the occur- 

 rence of the whitish fungous growth and the sickly and dying 

 condition of the pupae and caterpillars on June 21. At the time 

 I made the examination of the region about Wakefield with Mr. 

 Mosher the amount of infection was quite noticeable. From a large 

 number of nests containing pupae, which Mr. Mosher and myself 

 examined, I found from 70 to 75 per cent of the pupae infested 

 with fungi, all of which were either sickly or dead. The number 

 of infected caterpillars lying about on the trees and ground would 

 equal 80 or 90 per cent. This condition of affairs seemed to hold 

 good for much of the immediate region about Wakefield which we 

 examined. An examination about Maiden July 1 seemed to show 

 considerable infection of the pupae and caterpillars in that region, 

 but it was apparently not so general or marked as in Wakefield. 



As to the cause for the unusual outbreak of this fungus on 

 the brown-tail caterpillars and pupae, no doubt one, and perhaps 

 the most important, factor, was the condition of the weather at the 

 time of the first outbreak and following this period. At that time 

 there occurred more or less rain and cloudy weather, which ex- 

 tended over a period of some days. Such conditions are well 

 known to be particularly favorable for the development of many 



