1877.] 261 [Brewer. 



about and untouched. Dr. Brewer was absent from the city at the 

 time, and could not renew his investigations until September. Pre- 

 vious, however, to his leaving the city, he had noticed swarms of 

 these caterpillars in Charles and other streets, moving in the direc- 

 tion of the common, which on the 10th of July had been green, fresh 

 and uneaten, no insect anywhere even visible. On his return he sat- 

 isfied himself that the matter had been greatly over-stated. A care- 

 ful and very thorough examination of all the trees showed the 

 presence of less than a hundred cocoons, and all of these were on a 

 narrow strip north of the path from Spruce to Winter Street. 

 These gradually disappeared, but he did not see how. After the 

 heavy frost and rains preceding Nov. 5th, most of the trees became 

 leafless, and on a few small linden trees near Spruce Street were 

 observed several clusters of these cocoons, and all these trees were 

 swarming with sparrows, eagerly devouring them. The leaves of 

 these trees were whole and uneaten. The same thing was observed 

 on the 8th, and then the whole incongruity was explained by the 

 experienced and observing policeman in charge of that part of the 

 Common, Mr. T. H. Peabody. The caterpillar itself is never eaten; 

 is hairy coat makes it offensive or unattractive. The female moth 

 is wingless, and issues from her cocoon for a life only long enough 

 to deposit her eggs, which she protects by a viscid, frothy sub- 

 stance that hardens into a horn-like cover. In a dry condition this 

 is impenetrable. It can neither be torn from its place of adhesion, 

 nor be opened. It requires long and soaking rains to render it 

 soft and pliable, and in that condition it is readily eaten. Nearly 

 all the cocoons have now been removed, and only here and there, 

 under the shelter of some large limb, remain to demonstrate the 

 interesting explanation. 



Dr. Hagen, of Cambridge, commenting on these observations, 

 stated that during the ten years he had resided in Cambridge, he had 

 been much interested in the presence there of our singing birds. 

 During the summer just passed he had particularly noticed their 

 unusual abundance. The sparrows, too, were there in great num- 

 bers; wherever the singing birds were there were sparrows also, and 

 the latter certainly had not in any manner lessened the numbers of 

 the f jrmer. He thought that Dr. Coues, in his recent communication 

 published in the " Advertiser," was wrong, and his own observa- 

 tions convince him that the sparrows do not interfere with, or drive 

 away our singing birds. 



