Ecological and Behavior Notes 47 



records the fact that this large whirligig beetle was seen 

 in company with large numbers of the small variety, 

 Gyrinus aeneolus Lee. [E. A. Schwarz]. In the Mera- 

 mec river near Moselle, Mo., on September 23, 1916, an 

 oval area about 12 by 36 inches was so closely studded 

 with Gyrinus that a pencil could not be inserted between 

 them without disturbing them. This congregation was 

 in the water by the side of a fallen log, and looked like 

 an artifically made piece of bead-work, the whole set 

 off as with studied carelessness with about a dozen of 

 the large ones, D. assimUis. A disturbance of the water 

 would cause them to whirligig away, but one by one 

 they would glide back, and so the group would become 

 again intact, and all would be quiet again. The next day 

 they were in the same place and at 6 p. m., when it was 

 nearly dark, they w^ere likewise there. I suspect that it 

 is their habit quietly to spend the night in the water, 

 for I returned early the next morning and found no 

 change in their position or behavior. The mass re- 

 mained intact until noon that day, when I had to leave. 

 This is the only time I have seen the intimate association 

 of the two species, and I wonder if it is an accidental or 

 occasional occurrence, or if there is any mutual benefit 

 to be derived from the association. 



Silpha interrupta Fab. [E. A. Schwarz]. 



Aleochara lata Groh. [E. A. Schwarz]. These two 

 species were shaken out of the head of a dead robin at 

 Cliff Cave, Mo., in May 1916. 



Creophilus villosus [E. A. Schwarz]. About twenty 

 of these beetles, together with other species, were dis- 

 covered under the body of a dead and decaying chicken. 

 They all buried themselves immediately in the loose 

 earth under the hen, the moment the body was lifted up. 

 In digging them up with the trowel I found them always 

 in pairs, although not in actual copulo; it appeared as 

 though they might have just separated. A few minutes 

 after placing them in a glass jar, I found three pairs in 



