35 



gi-adually the higher the vegetation grew. For instance, all the cater- 

 pillars which had been feeding on the small willow brushes were already 

 dead. This brush, hardly 3 feet high, occurs here and there in front 

 of the two rows of woods. The dead caterpillars were readily seen, 

 as they were hanging all over the brush. Many of the caterpillars on 

 the birches were dying, but a considerable number of living individuals 

 was still present. In the colony of the high oaks, however, the wilt had 



Fig. 3. — Experiment, West Bedford, Mass. A. Dense birches. X- Exposure of 

 disease. B. Oaks and underwood. C. Field. D. Marsby meadow witb a few 

 scattered willows. 



not spread so much, although dead individuals were found in consider- 

 able numbers. 



On Sept. 23, 1910, the freshly laid egg clusters were estimated. We 

 made the interesting discovery that there existed no fresh clusters in 

 the row overgrown with birch. Thus, all the caterpillars, at least the 

 females, had been killed by Flacherie. To be certain of this fact the 

 crevices of the bordering stone wall were carefully examined, since 

 the gypsy moth female selects with preference such hidden places for 

 oviposition. But no fresh clusters could be found here. The other row 

 with the high oaks, however, proved to have a relatively large number 



