302 PROCEEDINGS OF THE NATIONAL MUSEUM vol. m 



noted that spiniger (the stercorarius of Fabre) oviposits in the fall 

 and then dies, new adults emerging the next fall. The adults of 

 stercorarius emerge in the fall and begin egg laying in the spring; 

 nearly grown larvae overwinter, and the adults do not appear until 

 fall of the second year. Geotrupes mutator was noted by Main ovipos- 

 iting at the same time as stercorarius, but the larvae of mutator com- 

 pleted their development during the summer and the adults came 

 out the same fall. Those species illustrate the three general patterns 

 of development for the European Geotrupes insofar as they have been 

 reported in the literature. A good summary of some of the biologies 

 of the Geotrupinae was written by Paulian (1949, pp. 1013-1015). 

 In this work Paulian has included a diagram of a typical burrow of 

 the European species of Geotrupes. 



Some variance has been noted due to climatic differences but, at 

 present, records are not available that would make possible any com- 

 parisons of developmental rates for the same species in different cli- 

 matic areas. I have tried to point out the close similarities between 

 the habits of the various European Geotrupes, even though several 

 are in different subgenera, which exhibit a number of morphological 

 differences. When differences such as different dates of oviposition 

 were found they often occurred between closely related species. 



Compared with the uniform habits of the European species, the 

 variation found in the habits of the American species was striking. 

 Available detailed biological information has been given after the 

 description of each species, and much of it is not repeated here. 

 Clark (1895, p. 61) stated that North American Geotrupes were en- 

 tirely dung or carrion feeders. If he had included fungi and decaying 

 or fermenting vegetable matter in his statement, it could be con- 

 sidered generally correct in reference to the adults. In the European 

 species, both the adults and larvae utilized the same substances for 

 food, while this association was not always the case for American 

 species. In the latter, the adults often were found feeding on one 

 food, later using an entirely different material to provision their 

 larval cell. Geotrupes blackburnii often uses dung for both the adult 

 and larval food. Geotrupes ulkei and splendidus commonly feed as 

 adults on fungi while the larvae develop on decaying leaves. Geotrupes 

 egeriei and hornii are usually fungus feeders as adults, but provide 

 their larvae with dung. 



The larval food differences mentioned above are not as great as 

 they might at first seem, if one takes into consideration an experiment 

 conducted by Fabre (1922, pp. 219-224) many years ago. The astute 

 French naturalist noted the similarity between old dung, which the 

 European Geotrupes larvae used for food, and the rotting leaves of the 

 forest floor. Taking some leaves, he rammed them tightly into a tube 



