306 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



the mouthparts of some of the genera. Structures used in sonifica- 

 tion have been mentioned by Arrow (1904, pp. 727-732), and the 

 evolution of the antennae was considered by Warnke (1934, pp. 

 217-224). 



The attractiveness of ammonia, indol, and skatol to several Euro- 

 pean species of Geotrupes was discussed by Warnke (1931, pp. 121- 

 199), and this motivated the use of the chemicals listed in tables 3 

 and 4. Vaternahn (1924, pp. 20-27) previously had noted that 

 certain chemicals would attract Geotrupes, and this fact was also 

 noted by Dethier (1947, p. 285). However, all of these studies 

 were very desultory and merely indicated the possibilities for further 

 investigations. 



Another line of investigation, the study of predators, parasites, 

 and commensals of the Geotrupinae, has not been discussed here. I 

 have observed both the adults and the larvae of the carabid Scarites 

 subterraneous Haldeman feeding on the larvae of Geotrupes black- 

 burnii. Also, several commensal organisms, Diptera and Collem- 

 bola, have been taken in the larval cells. This material was given 

 to J. Theodorides, who has already published several papers on the 

 parasites and commensals of Geotrupes (1949, 1950a, 1950b, 1951, 

 1952) and is continuing his work. Van Emden (1950, p. 190), in 

 his work on dipterous parasites of Coleoptera, expresses doubt that 

 any of these parasites occur on the larvae of Typhoeus. 



The most interesting case of parasitism on a species of Geotrupinae 

 known to me was recorded by Chapman (1869-1870). He stated 

 that he found as many as five or six pairs of Geotrupes stercorarius 

 (actually the species we now call spiniger, according to Main, 1917, 

 p. 19) burrowing under a piece of cow dung. He observed that they 

 made a vertical burrow 6 to 12 inches deep, merely compacting the 

 earth as they burrowed instead of bringing it to the surface. Six or 

 eight cells branched off this burrow, the beetles making the upper 

 cells first. Each cell, 4 or 5 inches long by 1 inch wide, contained a 

 single egg measuring ''^e inch in length," lying loosely in a cavity 

 near its terminal end. 



While making these observations. Chapman noticed an Aphodius 

 {A. porcus) entering the egg cavity of the larval cell. The Aphodius 

 then destroyed the egg, whether by eating it or not was not definitely 

 ascertained. After destroying the Geotrupes egg, the Aphodius then 

 laid its own eggs, using the food supply furnished by the Geotrupes to 

 nourish its own larvae. Whether this is a normal occurrence has not 

 been confirmed by subsequent investigators, but it does serve to 

 show the unexpected complexities that niaj be encountered, and the 

 need for more adequate biological information on the Geotrupinae 

 and the insects associated with them. 



