March, '08] ENTOMOLOGICAL NEWS. 121 



and securing it I found it to be another specimen of Necro- 

 phorus orbicollis. While securing this specimen I could plainly 

 hear the others about the mouse and, in addition to the strid- 

 ulating sounds, others were heard, as though the various 

 individuals were engaged in combat, the mandibles of one 

 grating on the chitinous parts of another ; and this is what 

 appeared to be taking place when I lighted my candle. 



At that time there were five specimens about the mouse and 

 four of these were fighting, in pairs, close to the carcass. 

 Their purpose was, evidently, to keep each other from reach- 

 ing the body of the mouse, and to do this they would seize 

 each other with their legs, and apparently their mandibles 

 also, and roll about in a most ludicrous manner, all the time 

 keeping up their stridulating sounds. At intervals they would 

 release their holds upon each other and return to the carcass, 

 only to renew the combat a little later. They did not appear 

 to mind the light much, especially if it was held at a distance 

 of a couple of feet or so. However, one took flight after a 

 short time, possibly owing to the light. 



Desirous to know how the stridulating sounds were pro- 

 duced, I seized one of the beetles with a pair of forceps and 

 held it up, and it was easy to see that the sound was produced 

 by a movement of the abdomen, apparently causing the upper 

 surface of one or more of the abdominal segments to rub 

 against the elytra.* 



I collected four of the beetles about the mouse all that I 

 could locate ac 8.20 P.M., and left the carcass for nearly an 

 hour. At 9.10 I again visited the place with my candle, and 

 was somewhat surprised at first to find the mouse gone from 

 the spot where it had lain. I soon located it, however, at a 

 distance of several inches from its former resting place, and 

 found three more of the beetles, which I collected, about it. 



My observations for the night closed at 9.50, when I again 

 visited the mouse and secured a single beetle. 



* Since making these notes, in 1906, the writer has noticed a single reference relative 

 to stridulation in IVecrophorus, viz., Third Report of the State Entomologist i>! Missouri, 

 p. 14, where Dr. Riley, in speaking of the stridulating organs of various Coleo|>tera, says: 

 " In the burying beetles (Necrophoridse) these rasps are situated on the fifth abdominal 

 joint, and are scraped by the posterior margin of the elytra." 



