BEETLES. 



385 



latter has the sides of the prothorax light red. As was noticed by Frisch, in 1740, in 

 describing the lai'va of the European S. obscura, these larvse are sometimes phyto- 

 phagous, and in the last few years numerous notices have been published of injury to 

 crops, especially to young sugar-beets, by larvae and imagos of the last- 

 mentioned species and of S. opaca and S. reticulata. Late experiments 

 have shown that some of these species prefer vegetable to animal food. 

 Sexual activity is great in Silpha ; and Dr. C. F. Gissler has written 

 of S. ratnosa, a species from the western United States : " They copu- 

 late every few hours, the male constantly pursues and annoys the female, 

 often snapping at the latter and biting into tips of elytra, for which 

 reason these (in collections) are so often found lacerated. The female 

 is often found buiTowed into the soil to escape the caressings of the via. im^— supim 

 male, and also for oviposition, which takes place there." The oval 

 eggs of this species, as Dr. Gissler has observed, are very large in comparison with 

 the insects' size, measuring about 0,1 of an inch in length, while the beetle is only 

 from 0.6 to 0.7 of an inch long. The larvae of Silpha are dark colored and flat, having 

 the characters already given for larvis of this family. 



The species of Necrophorus have ten-jointed antennae with a four-jointed round 

 club, and are of an elongated form, with red-spotted elytra, which are truncated at 

 their tips. On account of their habit of burying small dead vertebrate animals, in 



Fig. 457. • 



-Jiecrophoi'us vespitlio, grave-diggers at work. 



which they lay their eggs, these beetles are often called sextons or grave-diggers. This 

 habit makes these beetles useful scavengers. The largest North American species of 

 this genus is JST. americanus. It is 1.25 to 1.50 inches long, the top of the head is 

 red, the pronotum is of the same color margined laterally and behind with black, and 

 there are two red spots on the outer side of each elytron, one just anterior to its 

 middle and one near its tip. N. tomentosus is a common species in the northeastern 

 United States, and is about 0.75 of an inch long. Its prothorax is clothed with dense 

 yellow pubescences, and the red spots extend nearly across the elytra. Somewhat 

 resembling the last-mentioned species is N. vespiUio from Europe. N". germanicua, a 

 nearly black European species a little over an inch long, captures and devours Geo- 

 trupes stercorarius. 



The ScTDM^NiD^ differs from the Silphidse in having coarsely granulated eyes. 

 VOL. II. — 25 



