154 The Hessian Fly. and its Parasites. 



vieux, of which the following is a translation : — "Our wheat [in 

 the neighborhood of Geneva] has sustained the present month 

 of May, 1755, an injury, from which the grain cultivated by the 

 new husbandry has not been exempt. We found upon it a num- 

 ber of small white worms, which eventually turned to a chestnut 

 color : they fix themselves within the leaves, and gnaw the 

 stalks. They are commonly found between the first joint and 

 the root : the stalks on which they fasten, grow no more ; they 

 become yellow and dry up. We suffered the same injury in 

 1732, when these insects appeared in the middle of May, and did 

 such damage that the crops were almost annihilated." i, 299. 

 This passage was quoted by Col. Morgan, {Carey^s Anier. Miis. 

 1787, i, 530,) in the belief that the insect described in it was the 

 Hessian fly. The description is too imperfect to authorize a 

 positive assertion, but there seems to be little doubt that his opin- 

 ion is correct. 



In 1833, Mr. Dana sailed for the Mediterranean in the U. S. 

 ship Delaware. An opportunity was thus afforded him to make 

 personal exploration for the Hessian fly among the wheat fields 

 of the old world ; a work for which he was well prepared by his 

 thorough acquaintance with this insect in its various stages. His 

 examinations were rewarded with the most gratifying success, for 

 they proved that the Hessian fly is an inhabitant of Europe. 

 On the 13th of March, 1834, and subsequently, he collected sev- 

 eral larvas and pupas, from wheat plants growing in a field on the 

 island of Minorca. From these pupae, were evolved on the 16th 

 of March, 1834, two individuals of an insect which his recollec- 

 tions, (aided by a drawing of the Hessian fly with which he was 

 provided,) enabled him to pronounce to be the Cecidomyia De- 

 structor. More of the perfect insects were evolved in the course 

 of the month, one of which deposited eggs like those of the Hes- 

 sian fly. In letters dated Mahon, April 8 and 21, 1834, Mr. D. 

 sent me five of the insects, and several of the pupae. They 

 arrived in safety, and after a careful examination, I saw no good 

 reason to doubt the identity of this insect with the Hessian fly. 

 The Mahonese asserted that the insect had been there from time 

 immemorial, and often did great damage both there and in Spain. 

 On the 28th of April, 1834, Mr. D. collected from a wheat 

 field just without the walls of the city of Toulon in France, 

 several pupae and one larva like those before obtained. On 



