320 BOARD OF AGRICULTURE. [Pub. Doc. 



have typical examples of genera the larvae of which have been 

 considered especially distasteful to birds on account of the 

 hairs with which they are covered. The caterpillars of the 

 brown-tail moth would appear to be a particularly disagree- 

 able morsel to swallow. They are not only furnished with 

 long, bristly hairs, but the hinder segments of their bodies 

 are also supplied with minute, shorter hairs, which are barbed, 

 somewhat like the quills of the porcupine. These hairs pro- 

 duce very disagreeable consequences when brought in contact 

 with the human skin, into which they work their way and 

 there become the source of a serious and long-continued irri- 

 tation.* Many people in the district infested by the brown- 

 tail moth have been seriously inconvenienced by this cause, 

 and the services of physicians in the region infested have 

 been widely sought for a remedy. The irritation resembles 

 that caused by poison ivy, and no infallible cure has yet been 

 found. One would think that a bird which had inadvertently 

 swallowed one of these creatures would not care to repeat 

 the experiment ; but the observations of Mr. F. H. Mosher, 

 a very careful observer, show that as many species- of birds 

 feed on the brown-tail caterpillar as upon the gypsy cater- 

 pillar, and some species eat quantities of the former. Some 

 of the hairs of the gypsy caterpillar possess an irritating 

 property, so that the sensation produced by them, when 

 pressed against any tender portion of the human skin, is 

 similar to that produced by nettles. The hairs on the tent 

 caterpillar do not seem to possess either of these properties. 

 But even these larvae do not appear a tempting morsel, thickly 

 covered as they are with long hairs. The forest tent cater- 

 pillar also is supplied with hairs sufficient to secure it immu- 

 nity from the attacks of birds, if, indeed, such hairs constitute 

 any protection whatever. 



The Number or Hairy Caterpillars destroyed by Birds. 

 In order to get a definite idea of the comparative useful- 

 ness of the different species of birds in destroying hairy cat- 

 erpillars, I have asked Mr. Mosher to count the number of 

 caterpillars each bird was actually seen to eat during the 

 time occupied in some of its visits to trees infested by cater- 



* Proc. 10th Ann. Meeting Assn. of Ec. Ents., Bui. 17, p. 27, Prof. C. H. Fernald. 



