422 THE CANADIAN ENTOMOLOGIST 



everywhere — on the ground, over sticks, stones, logs, stumps, up 

 in the young pines above one's head, on the fence posts, up and 

 down the timbers of railroad bridges, in the water, and even on 

 the rails of the railroad. Some of the caterpillars were about one- 

 third grown, some were nearly mature, while a few were hanging 

 pendant, like fruit, preparatory to pupation. All about one could 

 hear the incessant rattle of their feeding, and the patter of their 

 falling excrement like the patter of summer rain. The ground 

 was covered with excrement. Thousands of the cast skins were to 

 be seen on the naked branches. Where the railroad train had been 

 blocked countless thousands of the dead and crushed caterpillars 

 were found, their bodies covering the ground for rods. In the 

 midst of this field of devastation stood willows, pines, roses, firs, 

 tamaracks, grasses and lupines all untouched. Just as I was leav- 

 ing the place, I noticed that the ground was covered with cater- 

 pillars, all crawling in the same direction. I found that they had 

 completely defoliated the ceanothus bushes where they had been 

 and were now on their way to find other food. 



Two days' later, in Spokane, I found a few acres of ceanothus 

 on a hill side completely defoliated as at Clayton. Here many of 

 the caterpillars had transformed to chrysalids. Several times they 

 were noticed to shake themselves violently until the bushes shook 

 from the effect. 



On July 7 I found millions of the caterpillars on the south slope 

 of Moscow Mt., Idaho. Some of these were parasitized by an 

 undetermined species of Braconid. 



On July 13, when I again visited the place of infestation at 

 Moscow Mt., I found that all caterpillars and all chrysalids were 

 gone. The caterpillars had evidently not migrated, for all around 

 as far as I could see the ceanothus had not been touched. Even 

 had the caterpillars migrated that would not explain the absence 

 of the chrysalids. I think that the total disappearance of these 

 caterpillars and chrysalids was no doubt due to birds. A similar 

 disappearance of all the caterpillars in the other districts visited 

 seems to confirm this opinion. 



These caterpillars were reported from the following places: 

 Chelan, Wn.; BroAvnsville, Wn.; Moscow Mt., Idaho; Nelson, B.C.; 

 Peachland, B.C., and Clayton, Wash. M. A. Yothers. 



