52 FAMILIES OF PETALOCERA WHICH LIVE 



seepius distincto. Pedes validi, tibiis anticis den- 

 tatis, spinis apicalibus instructis ; tibiis quatuorpos- 

 ticis apice seepius dilatatis. 



Observations. 



The characters hitherto given by entomologists to this 

 family, which is altogether the same as the Geotrupini of 

 Latreille, have been founded on the scrutiny of a few well 

 known European insects. To use such definitions there- 

 fore strictly would be equivalent to the exclusion of many 

 true Geotrupida from their natural place. Concisely 

 describing these insects, it may be said that they differ 

 from the Scarabaidcs by their corneous mandibles, and 

 from the Dynastida by their exserted labrum. But such 

 characters, like all others, are subject to an infinity of 

 shades, and may even altogether disappear in some insects 

 of this family, hereafter to be discovered. In such ano- 

 malous cases however, it will, I think, be always found that 

 the insects belong to extreme genera, or to those which 

 are close on the limits of other families. 



The Geotrupida are coprophagous or boletophagous. 

 Some extreme genera of the family, however, feed on roots, 

 and may often be considered as even lignivorous. The 

 types or central insects of the family, which are the bes$ 

 known, excavate cylindrical holes in the earth under their 

 food, and thus approach in their manners as well as form 

 to some of the Scarabaida. 



From the Geotrupida which I have had opportunities 

 of seeing, it may be calculated that the proportions of those 

 from within the tropics, from the temperate zones, and 

 from latitudes higher than 60°, are to one another nearly 

 as 2, 10, and 1 . And by way of proof that the Geoirupidce 



