9 



coming visible for a considerable distance. On a trip which I 

 made in June, 1910, to Eaymond, N. H., I saw thousands of 

 brown-tail moth caterpillars dead from muscardine, and com- 

 monly hanging in this characteristic manner. Since these 

 fungous diseases are extremely infectious, and propagate with 

 incredible swiftness, and since healthy caterpillars are much 

 inclined to gnaw at dead ones, the artificial production and 

 propagation of muscardine has been hopefully considered dur- 

 ing the last few years as a means of destroying the brown-tail 

 moth. 



There are two fungi, especially, which are responsible for 

 the death of most caterpillars ; these are Botrytis bassiana Bals 

 and Eniomophthora aulicae Eeichhardt. Experiments with 

 fungous diseases of the brown-tail moth are being conducted by 

 Mr. A. T. Speare, under the direction of Dr. E. Thaxter of 

 Harvard University.^ 



The pebrine or pebrina, which has become so notorious 

 through the great damage it has caused to the silk industry, 

 is the caterpillar disease which has been studied so far most 

 thoroughly. Caterpillars with this disease always have a 

 wet anus, and if they are hairy, the hairs on this region of 

 the body stick together. Smooth caterpillars also change their 

 color considerably; for instance, green caterpillars turn yellow- 

 ish, and are often mottled with dark, irregular spots; gayly 

 colored caterpillars lose their brilliancy. This disease does 

 not kill in a few hours or days, but the infected caterpillars 

 languish slowly, lose their appetite, and become transparent 

 and ill-nourished. They then shrink more and more, till 

 finally at death only the fiabby dry skin remains. Pebrine 

 appears preponderatingly in wet years, and its cause seems to 

 be lack of nourishment. The specific cause, however, the dis- 

 position, has not yet been absolutely determined. The carriers 

 of the disease are known under the name Gorpuscoli di Comalia, 

 and have been described by Lebert ^ as the fungus PanJiisto- 

 phyton ovatum (Micrococcus ovatus). Here it might be of 

 interest to cite from a review in " Deutsche Entomologische 



1 "Seventh Annual Report of the State Forester of Massachusetts, " 1910, pp. 98-101. 

 * "Berliner Entomologische Zeitschrift," 1858, p. 170. 



