DESTRUCTIVE INSECTS. 13 



Experience only tells us that at the Cape they come southwards 

 from the north. (i) 



11. It is well known that the locust sometimes multiplies in 

 Europe to such a degree as to dcA'astate provisions. Africa is 

 rarely free from its ravages, and of their infinite multitude we 

 have records from the earliest authors, fully confirmed by the 

 accounts of recent travellers. In France, Germany, Spain, Italy 

 and Russia, armies of locusts have appeared from time to time, 

 and with such devastating progress that " the laud is as the 

 Garden of Eden before them, and behind them a desolate wil- 

 derness." North America is not exempt from the plague of 

 insects, allied to locusts, and while in Europe they seldom pene- 

 trate further north than latitude 43^, their congeners have com- 

 mitted great ravages as far north as Lord Selkirk's settlement, at 

 Pembina, on the Red River, in latitude 54°, coming from the 

 Western prairies. 



12. The seventeen year locust, as it is popularly but erroneously 

 termed, is an American insect of most singvdar habits and des- 

 tructive character. Its appearance was first recorded about 

 Philadelphia in May, 1/15, and since that date "punctually at 

 the same month every seventeenth year, now certainly for nearly 

 one hundred and fifty years, has this extraordinary insect been 

 known to make its visit. No causes have aifected it during that 

 period, not even so far as relates to the month in which it 

 appears." (2) 



13. This remarkable insect appears in different parts of the 

 United States in separate broods, which have each their appointed 

 year for assuming the winged state, and propagating their specieis. 

 An entire brood hatches in a few days time, and countless mil- 

 lions of these large black flies (not true locusts) suddenly appear 



(1) Lake Ugasni. Page 285. 



(2) W. S. W. Ruschenberger, M.D., U.S.N. 



