8 FIEST ANKUAL REPORT OF THE STATE ENTOMOLOGIST. 



a possible loss of thirty milliotis of dollars in years of general prevalence 

 of the caterpillar.* 



From the census returns of the value of the agricultural products of 

 the United States, and estimates of injuries inflicted by certain insects 

 in several of the States, it has been computed that the aggregate an- 

 nual losses from injurious insects throughout the Union equals two 

 hundred miUion>i of dollars. \ 



B. D. Walsh, who was one of the most able of our economic ento- 

 mologists, gave it as his opinion that the United States suffer from the 

 depredations of noxious insects to the annual amount of three hundred 

 millio7is of dollars -X 



3. Excessive Insect Depredations in the United States. 

 The study of insects assumes an importance in this country far 

 greater than in any part of the world. Nowhere else are insect inju- 

 ries so serious as '.n the United States. Our several crops are attacked 

 by a larger number of insect pests, and the losses that they inflict 

 upon each are almost invariably in excess of those occurring in the 

 countries of Europe. Three causes have concurred and are mainly in- 

 strumental in producing this condition : 



I. The Importation of Injurious Insects. — Very few of our vari- 

 ous agricultural prod ucts are native to our soil. Nearly all of our fruits, 

 grasses, cereals, garden vegetables, and probably three-quarters of our 

 weeds are of foreign importation — mainly from Europe. With their 

 introduction very many of their attacking insects were also introduced 

 or subsequently brought hither, as, for example, the wheat-midge 

 {Diplosis tritici), the currant-worm {Netnatus ventricosus), the oys- 

 ter-shell bark-louse {Mytilasjyis pojnicorticis), the apple-tree plant- 

 louse [Ajjhis mali), the hop-louse {Aphis humuli), the grain-Aphis 

 [Siphonophora avence), several other species of plant-lice, the codling- 

 moth of the apple {Carpocapsa ponronella), the cabbage-moth {Ephesfia 

 interimnctella), the cabbage-butterfly {Pieris rapce), the currant-borer 

 {..Egeria tipuliformis), the asparagus-beetle (Crioceris asparagi), the 

 clover-root borer {Ilijlastes trifolii), the onion-fly {Anthomyia ceparutn) 

 and several other root-flies, the boll-worm or the corn- worm {Heliothis 

 armiger), and a number of destructive cut-worms (Agrotis c-nigrum, 

 A. baja, A. prasina, A. plecta, A. saucia, A. yjjsilon, Mamestra tri- 

 folii, Hadena Arctica), etc. 



Comparatively few of our native injurious species have been intro- 

 duced in Europe, consequently the number 'of those imported to this 



*Coinstock's Ee2}ort upon Cotton Insects, 1879, p. 70. 

 tPackard, in HayderCs Uh Annual Report U. S. G.-G. Surv. Terr., 1877, p. 591. 

 XAmerican Entomologist, \, 1868, p. 2. 



