Carrion Beetles, 



519 



Carrion Beetles. 



In July last the Board received from Scotland specimens of 

 beetles which were found to be very numerous in a turnip field, 

 although they were not definitely stated to be feeding on the 

 plants. They proved to be one of the Carrion Beetles {Silpha 

 rugosa), closely related to the two Beet Carrion Beetles {Silpha 

 opaca and 5. atrata). Both the latter species are injurious to man- 

 golds, the larvae eating the leaves and stem, and often destroying 

 a crop entirely. Silpha rugosa nearly always occurs with them, 

 and is probably the commonest member of the genus ; but there 

 is no record of this species doing any harm to crops, as in the 

 case of the two closely related species. 



The larvae and also the adults of the Silphidae are normally 

 carrion feeders, numbers of these three species being usually 

 found in June in and under any dead carcase lying about in the 

 fields. But the two species vS. opaca and vS. atrata frequently 

 abandon their carnivorous habits and attack mangolds and beet- 

 roots. Canon Fowler also records finding the larvae of a number 

 of this genus on the roots of plants in the Isle of Wight. It is 

 therefore possible that 6". rugosa may sometimes become vege- 

 tarian in habit. Miss Ormerod mentions the Beet Carrion beetle 

 (S. opaca) as occurring also on the potato, and devouring spurrey r 

 so that it is possible that S. rugosa may similarly attack various 

 plants and not one in particular. 



The larvae of ^S. rugosa are moderately broad, with the edges 

 of the thoracic {i.e., first three) segments rounded, those of the 

 remaining segments projecting. The body ends in two processes 

 called cerci, which in this species are long — at least three times 

 as long as the anal process between them. The head is large 

 and projecting. When full grown, which is usually by the 

 middle, but sometimes not until the end of July, the larvae bury 

 themselves in the soil to a depth of from three to four inches, 

 and turn to pupae. In three to four weeks the beetles appear 

 from the pupae, and these beetles apparently live through the 

 winter. 



As there seems to be a possibility of these carrion feeders 

 becoming destructive, it may be advisable to take steps to clear 

 turnip fields, where they are numerous, of these insects. For 



