PROBABLE ORIGIN OF CORNISH PLUSIA NI. 299 



"After trying in vain to obtain any intelligence of shrubs or 

 unsawn wood being imported from South America, a remark of 

 my sister's turned my thoughts in another direction. She told 

 me that the common wasp was often very troublesome to butchers 

 by its taste for raw meat. Now there is a regular trade between 

 Penzance and South America in raw hides, and it occurred to 

 me as possible that the South American wasps might have 

 settled on the hides, and so have got wrapped up and entangled 

 in them. It was also ascertained that the ship conveying the 

 hides arrived at Penzance on the 25th of July, 1866, and the 

 Polistes was captured about 15th August. In 1867 the same ship 

 entered the port of Penzance on 31st of July, and the Polistes 

 was again taken during the first week of August." The captain 

 of the vessel, when interrogated about the wasp, said they " no 

 doubt came from his ship, as he had seen hundreds about it 

 when sailing down one of the branches of the La Plata." 



"The explanation," Mr. Smith thought, "fully accounted for 

 the capture of the Polistes, and at the same time suggested a way 

 by which many carrion beetles may be conveyed to this country 

 in a way that might not occur to entomologists who pick up such 

 insects in the neighbourhood of Penzance, as well as near ports 

 in other parts of the country." He also mentions that Mr. 

 Douglas captured the same species of Polistes at St. Katharine's 

 Docks, and Mr. Nicholas Cooke took another in the office of a 

 wool warehouse at Liverpool. 



My own opinion is that P. ni {brassicce, Riley) came over with 

 Polistes ; it is common in Brazil and other parts of South America, 

 and it is this insect which is becoming such a nuisance in the 

 States : the conditions were there for making the voyage. We 

 know that moths and caterpillars do find their way on board vessels, 

 and cocoons may be made up in wool or hair. No captures of P. 

 ni were made till after the arrival of the vessel with Polistes. P. ni 

 is a rare continental species, and is almost unknown in the north 

 of Europe. An immigrant from South Europe would be most un- 

 likely to land at the far west. All the specimens here have been 

 taken either at the west or straggling away from it — Cornwall, 

 Devon, Dorset, and Portland, but the metropolis is at Penzance. 



Miss Carne's specimen was caught in May, and showed that 

 the species was double-brooded, and had been bred in the country; 

 and Mrs. Richardson's as well as the more recent Penzance 

 experience prove that the species breeds freely enough in this 

 country. So that, if my surmise is correct, this Plusia has been 

 an inhabitant of Penzance for nearly forty years. 



In fact, I am persuaded that the North American, the British, 

 and in all probability the European ni too, only from an earlier 

 ^Deriod, all hail from " the country where the nuts come from,'" 

 or thereabouts. 



Folkestone : Nov. 1903. 



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