HYMENOPTERA. 437 



by various kinds of gall-insects, and the maggots, hatched 

 from these eggs, devour the young of the gall-fiies. Nor do 

 they destroy these alone; they prey upon many other larvae, 

 especially caterpillars, and also on pupro or chrysalids. Some 

 of them are egg-parasites, puncturing the eggs of other insects, 

 and depositing therein their own tiny eggs. They are the 

 minute ichneumons [Idmcumoncs minuti) of Linnteus, and, 

 like the true ichneumon-flies, they are eminently useful in 

 checking the increase of the noxious tribes. Such being the 

 known habits and services of the greater part of the Chalcid- 

 ians, it may seem singular that any doubt should exist in 

 regard to others of them. There are, however, some kinds 

 which have been thought to produce galls themselves, instead 

 of being the parasites of gall-insects; certain species wearing 

 indeed the form of a Chalcidian, but appearing to have the 

 habits of a Cynips. These species belong to the genus Eiiry- 

 ^oma, which, though agreeing in structure with the Chalcidians, 

 Professor Nees von Esenbeck was inclined to place among the 

 CvNiPiD.E, because he took them to be gall-makers. Mr. West- 

 wood* controverts this opinion; and Dr. Ratzeburgf considers 

 it as founded upon error. It may nevertheless be correct, if 

 there be no mistake in the result of observations made upon 

 the insects, called barley-straw insects and joint-worms, that 

 produce gall-like swellings upon the stems of barley and of 

 wheat in this country. 



In the years 1829 and 1830 several communications were 

 published in the eighth volume of Fessenden's " New England 

 Farmer," \ respecting a disease of barley-straw, produced by 

 the punctures of insects. The first account of this disease 

 that has fallen under my notice, is contained in an extract 

 from a letter, dated August 16th, 1829, from the Honorable 

 John Merrill, of Newburyport, to Mr. Fessenden ; wherein it 

 is stated, that the barley, in the neighborhood of Newburyport, 

 yielded only a very small crop; on some farms not much more 



* "Modern Classification of Insects," Vol. II., p. 161, note, 

 t "Die Ichneumonen der Forstinsectcn." I., p. 172. 



t Pages 43, 138, 217, 299, 330, and 402. Also Vol. IX., p. 2., and Vol. X., 

 p. 11. 



