THE BROWN-TAIL MOTH. 



61 



This gives us an average of 26.3 larvse per web emerging 

 unharmed ; the average normal web contains about 290 

 larviB. 



It is preferable, where circumstances permit, to burn the 

 webs in a furnace or stove, thus insuring their complete de- 

 struction. Where the webs are burned in a bonfire in the 

 field, it often occurs that a part become covered with ashes 

 and are not consumed. In a case noticed by one of the 

 writers, some years ago, a number of webs that had been 

 partly scorched in a bonfire were still found to contain liv- 

 ing insects. Silk is an excellent non-conductor of heat, as 

 well as of cold ; and in this case, while the webs protected 

 the caterpillars from the rigors of winter, they also preserved 

 a part of them unharmed from the action of fire. 



Spray In fj. 



There will always be cases where the work of web de- 

 struction has been neglected, from one cause or another, — 

 too often from the indolence of the property owner, ^^'hcn 

 the cateri)illars emerge in the si)ring and conuncnce feeding 

 on the young buds and leaves, the best remedy is to spray 

 the tree promptly and thoroughly Mith arsiMiate of lead, 

 using o or 4 pounds to i^0 gallons of water. The insecticide 



