434 INSECTS INJURIOUS TO VEGETATION. 



maggots, were found, by John M. Gourgas, Esq., of Weston, 

 Massachusetts, to be transformed to small flies, which were 

 thought, by some persons, to be the same as the Hessian flies. 

 In the summer of 1831, myriads of these flies were found alive 

 in straw beds in Gloucester ; the straw having been taken from 

 the fields the year before. An opinion at that time prevailed, 

 that the troublesome humors, wherewith many persons were then 

 afflicted, were occasioned by the bites of these flies ; and it is 

 stated that the straw beds in Lexington, being found to be in- 

 fested with the same insects, were generally burnt.* If any in- 

 convenience really arose from sleeping on these beds, it is far 

 more likely to have been occasioned by the bites or stings of 

 parasitical insects, than by those of any insect like the Hessian 

 fly. That vast numbers of parasitical insects, closely resembling 

 the Eurytoma destructor^ come out of the diseased straw will be 

 shown hereafter. Mr. Gourgas observes,! that when the barley 

 is about eight or ten inches high, the effects of the disease in 

 it begin to be visible by a sudden check in the growth of the 

 plants, and the yellow color of their lower leaves. If the butts 

 of the straw are now examined, they will be found to be irregu- 

 larly swollen, and discolored, between the second and third 

 joints, and, instead of being hollow, are rendered solid, hard, and 

 brittle, so that the stem above the diseased part is impoverished, 

 and seldom produces any grain. Suckers, however, shoot out 

 below, and afterwards yield a partial crop, seldom exceeding one 

 half the usual quantity of grain. " It is evident," says Mr. 

 Gourgas, " that the soundness of the grain, raised in a blighted 

 field, is not affected thereby in the slightest degree,; the seed 

 (eggs) to perpetuate the disease from year to year is lodged in 

 the straw, which, when hatched, are the worms " before men- 

 tioned. Dr. Andrew Nichols, of Danvers, states, | that these 

 worms are about one tenth of an inch in length, and of a yellow 

 or straw color ; and that, in the month of November, they ap- 

 peared to have passed to the chrysalis state. They live through 

 the winter unchanged in the straw, many of them in the stubble in 



* " New England Farmer," Vol. X , p. 11. t The same, Vol. VIII., p. 299. 



J The same, p. 138. 



