304 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



While all of the data accumulated have been given after the tax- 

 onomic discussion of each species, a general summary of the available 

 biological information can be found in table 2. In this table one of 

 the most noticeable and constant of the interspecific differences shown 

 is the variation in the burrow types. The burrows of splendidus are 

 similar to those of blackburnii, but are sHghtly deeper and contain 

 leaves instead of dung. The burrows of egeriei and hornii are con- 

 siderably deeper than blackburnii and splendidus and both use old cow 

 dung as larval food. However, hornii has a number of cells branching 

 off a burrow, as has been noted for European species, while egeriei only 

 had a single cell in the two cases found. An interesting subspecific 

 difference in burrow habits may possibly exist between the eastern 

 splendidus and the western splendidus miarophagus. I found the 

 eastern subspecies making a single cell of dead leaves at the bottom of 

 its burrow, while Dawson (1922, p. 196) recorded finding a burrow of 

 s. miarophagus with several cells branching off the burrow, the pods 

 being composed of fresh cut grass. 



When considered in conjunction with adult and larval morphology, 

 the burrow and food characteristics seem to have possible taxonomic 

 importance, at least in a consideration of phylogeny and in generic and 

 subgeneric groupings. On the basis of adult morphology I would 

 consider that, of all the North American Geotrupini, Geotrupes hornii 

 is the species most closely related to Geotrupes stercorarius. The same 

 conclusion could be reached from a comparison of their burrows. The 

 diagram of the bmTow of Geotrupes hornii (pi. 10, fig. 5) closely approx- 

 imates ones given for stercorarius. I believe, on the basis of adult and 

 larval morphology and on the burrow characteristics, that the present 

 subgeneric groupings of the North American Geotrupini are in need 

 of some rearrangement, but hesitate to do so until something is learned 

 about the larvae of Geotrupes opacus, semiopacus, and balyi. 



In this paper I have elevated Blanchard's subgenus Peltotrupes to 

 generic rank because of certain adult and larval characteristics which 

 are not known to exist in any Geotrupes. Biological differences are 

 in strong support of this generic separation. 



The adults of Peltotrupes are active in the winter months, with 

 oviposition occurring largely in January, February, and March. 



The deepest burrow of any species of Geotrupes known to me 

 did not approach 4 feet, even in the areas where Peltotrupes occurred. 

 The burrows of Peltotrupes averaged 6 feet deep with one burrow 

 reaching 9 feet. One great difference noted between Peltotrupes and 

 the known Geotrupes was in the method of packing the larval cell. 

 In Geotrupes the food material, whether it was dung or leaves, was 

 tightly packed so that the cell retained its shape when removed from 

 the ground. The cell of Peltotrupes, which was a conglomeration of 



