6 First Report on Economic Zoology. 



EOOT CHOP PESTS. 

 Silpha rugosa, L., on Turnips, and other Silj^hidce. 



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

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

 Board, was appearing in gi'eat numbers on a turnip crop. Both of 

 the latter species are injurious to mangolds, the larvae devour the 

 leaves and stem and often destroy a crop entirely. Silpha. rurjosa 

 occurs with them nearly always and is proljably the commonest 

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

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

 harm to crops, such as occiu's wdth the two closely related Carrion 

 Beetles. 



The larvse of tlie Silphid?e and also the adults are normally 

 carrion feeders, lumbers 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. opaxa and >S'. atrata. 

 frequently give up theii- carnivorous habits and attack mangolds and 

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

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

 therefore, possible that S. rugosa. may sometimes become vegetarian 

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

 coiTespondent make any such statement. 



The larvffi of S. rugosa are moderately Ijroad with the edges of the 

 thoracic (i.e. first tliree) segments rounded, those of the remaining 

 segments projecting. The body ends in two processes called cerci, 

 which in tliis species are long, at least tlu'ee times as long as the 

 anal process between them ; the head is large and projecting. 



Wlien 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 pupa?. 



After from three to foiu- weeks beetles appear from these pupce, 

 and these beetles apparently live through the winter. 



]\Iiss Ormerod records the Beet Carrion Beetle {S. opiaxa.) on 

 potato and also as devoming the Spurrey {Spergukt 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 shoirld be taken to have the turnip and other fields 

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

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



