352 



THE MONTHLY BULLETIN. 



tain were throughout much of their territory completely defoliated, 

 and presented a brown and seared appearance. Much of this was dead 

 or dyijig, and, as a result, quite inflammable. The brush here is com- 

 posed primarily of two species of Ceanothus, the thick or broad leaved 

 species, Ceanothus velutinus, Dougl., and the so-called snow-bush, 

 Ceanothus cordulatus, Kell., and these plants seemed to be the preferred 

 food plants. These caterpillars appeared about the first of June and 

 by the middle of the month had made so many silken tents that the 

 brush areas presented the appearance of being covered with in- 

 numerable paper bags, sometimes as many as twenty or more being 



Fig. 90. — Defoliated brush showing tents of caterpillars (Malacosoma 

 fragilis), McCloud, Cal. C Original.) 



found on a single plant. By about the beginning of July a certain 

 portion had completed their gro\\'th and started to migrate. These 

 were soon joined by hosts of undeveloped specimens which had eaten 

 up all of the available food in their neighborhood and were seeking 

 other feeding grounds. They were to be found everywhere on the 

 trails, roads and railroad tracks. They were a decided nuisance, in- 

 vading the lumber and construction camps and getting into the tents 

 and over everything. They seemed to have a liking for traveling along 

 the railroad rails. Their crushed bodies made the rails so slippery that 

 the engine could not get traction, and as a result caused many delays 

 and much expense, and was a source of great danger, particularly with 

 the heavy logging trains. The railroad authorities of McCloud at first 

 stationed men with brooms on the fronts of the engines, who SAvept 

 them ofi'. This was fairly successful at first, but later on not so much 

 so because large numbers of the caterpillars were inevitably crushed in 

 the process. Cresol sprinkled along the sides of the roadbed retarded 

 the migrating hosts for but a few moments. Ditches which were being 

 dug about the camps, and were quite effective for a time in keeping 

 out the pests, could not be used by the railroad because of the expense. 

 At last some of the railroad managers devised an arrangement whereby 



