TUB MONTHLY BULLETIN. 



353 



they could conduct steam from the engine through tubes and blow it 

 forward along the tracks ahead of the train. This was very successful 

 for it cleared the tracks without crushing the insects and at the same 

 time so stunned or killed them that they could not return. 



Figure 91 will give an idea of how this apparatus appears. In cer- 

 tain places along the McCloud railroad from Sisson to IMcCloud the 

 dead caterpillars were so banked up that you could have shoveled 

 them up by the bushel. 



The caterpillars though primarily hatching and feeding upon the 

 two species of bush ceanothus. an occasional manzanita and the wild 

 rose and gooseberry where found when once they had eaten up all of 

 their accessible normal food and had become ravenous and been obliged 

 to travel, attacked almost everything. I found them on the "squaw 

 carpet," Ceanothus prostratus, Benth.. on the wild cherry, the willow, 

 many of which were completely defoliated, and on many cultivated 

 plants. A few of them had been able to get as far as a few apple 



Fig. 91. — Engine with attaclinient fur blowing oft" caterpillars with steam. 



(Original) 



trees and they were devouring the leaves of these with such relish 

 as their relatives do elsewhere. None, however, seemed to have attacked 

 any coniferous tree. By the second week of July, the developed cater- 

 pillars were commencing to spin their cocoons and these yellow cocoons 

 were to be seen everywhere, certain areas of the brush being so 

 sprinkled with them that they were very evident even from the car 

 windows. Numbers of these which I brought home with me hatched, 

 the moths emerging between the twenty-fourth and the thirtieth of 

 July. 



The outbreak had apparently for some unknown reason gone beyond 

 the action of the controlling factors. j\Iany of the caterpillars had 

 been parasitized by various species of tachinid flies, the white eggs 



'For the pictures taken. I am indebted to my friend Dr. Robt. Legge of McCloud 

 wlio very kindly put himself out for me. 



