620 THE POPULAR SCIENCE MONTHLY. 



THE ENEMIES WE IMPOKT. 



By Prof. SAMUEL LOCKWOOD, Ph. D. 



IT would seem as if every grain brought its "bane. The Agricultural 

 Department at Washington has done a good deal for agriculture 

 in the importation and distribution of foreign seeds, slips, and plants. 

 In this way have been secured to the country many of the choicest im- 

 proved plants from abroad, and many entirely new to our gardens. 

 But it is to be feared that, in some instances unavoidably, and in 

 others from want of care or skill, or both, the eggs and larvae of for- 

 eign insect-pests have been introduced, and are to-day troublesome to 

 the husbandman, and a source of mischief and loss to the interests of 

 the nation at large. If that man, or that art, is a public blessing that 

 makes a spear of wheat grow where the land was sterile before, or 

 makes that bear twofold that before did little more than barely repro- 

 duce its kind, surely, then, that is a pest and misfortune that appears 

 as a new destroyer of the anticipated harvest. So far as size is con- 

 sidered, the little fly introduced in the provender of the Hessian sol- 

 dier, in 177G, is contemptible; yet it was destined to become an enemy 

 more formidable than the troops that brought it. So diminutive, in- 

 deed, is this pest, that many a husbandman has never seen it to know 

 it, and, in fact, only knows it from its sad depredations on his honest 

 labor ; which are such that all the combined whirlwinds and destructive 

 storms that have ever swept over portions of our land have not robbed 

 the national wealth so much as this almost invisible, tiny creature, that 

 dances in the sunbeam ; which science well names Cecidomyia de- 

 structor, and which tradition calls the Hessian fly. 



In Freehold, N. J., in the autumn of 18V0, 1 detected a new-comer 

 making terrible havoc with the cabbage. This esculent was entered 

 from without, and almost honey-combed by a small green caterpillar, 

 that I had never seen before. It was soon determined to be the Pieris 

 rapae, or cabbage-caterpillar of Europe. The parent was a pretty but- 

 terfly, mainly white, with black spots on the wings. It first appeared 

 on this continent at Quebec, and made its noxious power felt in the de- 

 struction of the cabbages to the amount of many thousands of dollars 

 in that neighborhood. It soon came into Northern New England, and 

 in 1869 was found in the gardens within a few miles of New York. At 

 Freehold, of course, it was stretching south. It soon reached Phila- 

 delphia. Last summer it was at home at Baltimore, and this June it 

 has appeared at Washington. The terrible little beauty is thus belt- 

 ing the land with a scourge. 



Among the insect pests that have become celebrated because of its 

 fearful capacity of increase, the grasshopper deserves mention. It is 



