6 First Report on Economic Zoology. 



EOOT CHOP PESTS. 

 Sil'pha riigosa, L., on Turnips, and other Silphidw. 



One of the Carrion Beetles, Silpha rugosa, L., closely related to 

 the Beet Carrion Beetles (Silpha opaca and >S'. atrata), sent to the 

 Board, was appearing in great nninbers on a turnip crop. Both of 

 the latter species are injurious to mangolds, the larv?e devour the 

 leaves and stem and often destroy a crop entirely, Silplia rugosa 

 occurs with them nearly always and is probably the commonest 

 member of the genus, being found almost everywhere, but there have 

 been no observations made on this species showing that it does any 

 harm to crops, such as occurs with the two closely related Carrion 

 Beetles. 



The larviie of the Silphidiie and also the adults are normally 

 carrion feeders. Numbers of these three species may usually be 

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

 fields, but as previously stated the two species S. opaca and >S'. atrata 

 frequently give up theii' carnivorous habits and attack mangolds and 

 beetroots. Canon Fowler also records finding the larv?e of a member 

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

 therefore, possible that S. rugosa may sometimes become vegetarian 

 in habit, but no mention has been made of this, nor does the Board 

 correspondent make any such statement. 



The larvre 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 l)ody ends in two processes called cerci, 

 which in this species are long, at least tlu'ee 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, they bury themselves in the soil to a 

 depth of from three to four inches and turn to pup?B, 



After from three to four weeks beetles appear from these pupse, 

 and these beetles apparently live through the winter. 



Miss Ormerod records the Beet Carrion Beetle {S. opaca) on 

 potato and also as devouring the Spurrey (Sjyergula arvensis), and 

 it is thus possible that we may get S. rugosa working in a similar 

 manner on various plants and not on any one in particular. 



As there is a possibility of these carrion beetles becoming 

 destructive, steps should l)e taken to have the turnip and other fields 

 cleared of them and any of their larvse. To do this is a compara- 

 tively easy matter if we employ natural traps in the form of dead 



