OF WASHINGTON. 77 



locust to attain considerable size, but that the increase of the 

 locust-borer, Cyllene robinice, was largely the cause of this. 



He said, further, that the nature of the soil had much to do 

 with the successful growth of the tree, instancing in this con 

 nection that at Davenport, Iowa, and other localities that he 

 was aware of, on high and dry land with a limestone subsoil, 

 it became a large tree, but in low, moist ground it was seriously 

 attacked. 



Mr. Schwarz stated, in reply to Mr. Howard, that his paper 

 had been prepared two months previously, and he admitted 

 that the various leaf-miners, and particularly those mentioned 

 by Messrs. Riley and Howard, had greatly increased outside 

 of the District. He stated also that in Europe the tree was 

 a magnificent one. 



Mr. Howard stated that the freedom of the locust trees in 

 the grounds of the Department from leaf-miners was doubtless 

 owing to the fact that the leaves were regularly raked up and 

 disposed of in the fall. 



Prof. Riley called attention to the curious fact that in the 

 case of the L,ocust and Hickory Cyllene the larva of one was 

 footless and the other was provided with feet, and that this 

 marked structural difference in such closely allied species also 

 occurred in the case of the genus Prodoxus and Pronuba, and 

 forcibly illustrated the folly of attaching too great classi- 

 ficatory value to larval characters. 



Mr. Schwarz exhibited the burrows of some Scolytid 

 beetles, and explained them by the following remarks : 



NOTES ON THE BREEDING HABITS OF SOME 

 SCOLYTIDS. 



BY E. A. SCHWARZ. 



XYLOTERUS POUTUS. This is an abundant, and, at the 

 same time, very destructive species, yet very little seems to be 

 published of its food-habits. Mr. J. W. Randall, who de 

 scribed it as Tomicus gularis, found it ' ' about the sap of 

 newly-cut maple trees in April," and Dr. J. A. L,intner found 

 it "depredating upon maple trees." Some years ago it 

 attacked and killed, within less than two years, two beautiful 

 trees of silver birch (Betula alba) in the grounds of Mr. Bela 



