188 



closely allied to it, and probably also belonging to the genus 

 Cecidomyia, 



HERRICK TO HARRIS. 



New Haven, March 29, 1841. 



The supposition that the Cecidomyia destructor lays her eggs 

 on the ripening grain, involves various improbabilities and im- 

 possibilities. 1. The egg is very delicate, covered only by a 

 fine cuticle, and if on the seeds of wheat, would be crushed 

 when they are thrown together. 2. It Avill hatch within ten to 

 twenty days after it is laid. The wheat is sown in two or three 

 months after ; of course the larvae must have all perished, for 

 they cannot eat grain, but can ouly suck the juices of the plant. 

 3. If the egg is hatched in the earth, it is scarcely possible that 

 the larva can crawl to its usual position, between the sheath of 

 the leaf and the stalk. 4. Whence come all the larvae which 

 we find in the young wheat in the spring? — not to ask the 

 origin of the eggs themselves, which we may find abundantly in 

 April and May on the leaves of the young plants. 



Having planted wheat in my garden every year since 1832, 

 and watched with great assiduity and interest the operation of 

 the Hessian Fly, both there and in open fields, in many hun- 

 dred instances, I feel absolutely sure that this insect does not 

 lay her eggs on the head of the wheat, but that she does de- 

 posit them on the (upper surface of the ligula of the) leaves 

 of the young wheat, both in autumn and spring. 



It is a very proper inquiry, — what do these people actually see 

 who assert that the Hessian Fly lays her eggs on the head of 

 the wheat? I have long been inclined to believe that the Tijni- 

 la (^Cecidomyia) tritici of Kirby attacks wheat in this country, 

 and also that the moth (allied to the Tinea granella Linn.) de- 

 scribed in Duhamel's Histoirc d'un Insecte, etc., is also to be 

 found with us. In Jas. Mease's Archives of Useful Knowledge, 

 Phil., 1812, Vol. II, p. 45, is an article by Jno. Sorain of Tack- 



