1 888.] NEW-YORK MICROSCOPICAL SOCIKIV. 14-7 



placed in glass jars, like that just mentioned, fitted with their 

 respective metal covers. 



One of these beetles I exhibit here alive to-night. This one 

 has accomplished metal-working precisely like that of the first 

 specimen, and I have had no little satisfaction in watching the 

 process, and in listening to the sound, caused by the mandibles 

 while cutting the chips from the cover. During this operation 

 the beetle passed the feet through the ventilating holes, and 

 hung suspended, back downwards, from the under surface of 

 the cover. This metal is pewter ; probably composed of three 

 parts of lead, and one part of tin, and is about one thirty-second 

 of an inch in thickness. Under experiment it was found that a 

 force of 369 grammes was necessary to remove chips corres- 

 ponding to those cut by the beetle. 



Your attention is called to the fact that the cutting edges of 

 the mandibles of the dead beetle are in good condition, while 

 those of the living beetle are badly broken. Both insects did 

 the same kind of work, under the same circumstances ; but I 

 am unable to account for the different effects upon the tools 

 they employed. 



THE LARV^ OF THE STAG-BEETLE, EATING 

 RAILROAD TIES. 



BY PROF. SAMUEL LOCKWOOD, PH. D. 



{Read May a,th, 1888.) 



On the 28th lilt., I received some old ties, which, to be re- 

 placed by new ones, had just been taken up from the track of 

 the Pennsylvania Railroad, where it passes through the village 

 of Freehold, New Jersey. They were of oak, and measured 

 eight feet and six inches in length, with an average thickness of 

 about seven inches. The ties being hewn and not sawed, the 

 width varied a great deal, depending on the age of the trees 

 employed. 



These old ties were purchased for the purpose of building a 

 barricade. 1 noticed that while the under and the upper sur- 

 faces were sound, the sides were dozey, or decayed. Wishing 

 to know the depth of this condition of the wood I used a chisel, 

 and found numbers of the larvae of a lamellicorn beetle, each 



