DAMAGES BY INSECTS. 353 



worm, and chinch bug." According to Dr. Shimer's estimate, 

 says Mr. Riley, which may be considered a reasonable one, " in 

 the year 1864 three-fourths of the wheat, and one-half of the 

 corn crop were destroyed by the chinch bug throughout many 

 extensive districts, comprising almost the entire North-West. 

 At the annual rate of interest, according to the United States 

 Census, in the State of Illinois, the wheat crop ought to have 

 been about thirty millions of bushels, and the corn crop about 

 one hundred and thirty-eight million bushels. Putting the cash 

 value of wheat at $1.25, and that of corn at 50 cents, the cash 

 value of the corn and wheat destroyed by this insignificant little 

 bug, no bigger than a grain of rice, in one single State and one 

 single year, will therefore, according to the above figures, foot 

 up to the astounding total of oyer seventy-three millions op 



DOLLARS ! " 



The imported cabbage butterfly (Pieris rapa), recently intro- 

 duced from Europe, is estimated by the Abbd Provancher, a 

 Canadian entomologist, to annually destroy two hundred and 

 forty thousand dollars' worth of cabbages around Quebec. The 

 Hessian fly, according to Dr. Fitch, destroyed fifteen million 

 dollars' worth of wheat in New York State in one year (1854). 

 The army worm of the North (^Leucania unipimcia), which was 

 so abundant in 18G1, from New England to Kansas, was re- 

 ported to have done damage that year in Eastern Massachusetts 

 exceeding a half million of dollars. The joint worm {Isosoma 

 hordei) alone sometimes cuts off whole fields of grain in Vir- 

 ginia and northward. The Colorado potato beetle is steadily 

 moving eastward, now ravaging the fields in Indiana and Ohio, 

 and only the forethought and ingenuity in devising means of 

 checking its attacks, resulting from a thorough study of its 

 habits, will deliver our wasted fields from its direful assaults. 



Tliese are the injuries done by the more abundant kinds of 

 insects injurious to crops. We should not forget that each fruit 

 or shade tree, garden shrub, or vegetable, has a host of insects 

 peculiar to it, and which, year after year, renew their attacks. 

 I could enumerate upwards of fifty species of insects which prey 

 upon cereals and grass, and as many which infest our field crops. 

 Some thirty well known species ravage our garden vegetables. 

 There are nearly fifty species which attack the grape-vine, and 

 their number is rapidly increasing. About seventy-five species 

 45 



