290 



THE farmers' cabinet 



VOL. I. 



colorless,* rounded at tip, reaching beyond 

 the abdomen ;—/eet long and slender; — ab- 

 dovien slender, in the female, rendered acute 

 and extensive by the protrusion of the oviduct. 

 Length, about ihree-twentieths of an inch. 



Under the microscope, the body appears 

 liairy ; the join/s of the antennce are verticil- 

 late with short hairs, especially in the female ; 

 in the male sex, the joints are separated by a 

 central fine thread, in the female, approxi- 

 mated ; the edges of the wirigs are finely 

 fringed with short dark colored hairs. 



1 would advise those who may not already 

 have done so, to procure tlie fly for exami- 

 nation. This may easily be done at the pro- 

 per season, (when it is in the pupa or flaxseed 

 state, the beginning of the sixth month,) by 

 pulling up the infected plant and placing the 

 root and part of the stem in a glass jar tied 

 over with gauze to prevent their escape. 



What are the habits of the Wheat Fly 1 

 The habits of many animals are more con 

 cealed from observation, than the animals 

 themselves. It is so in the present instance. 

 Enough, however, has been observed of the 

 habits of the wheat fly, to afford data, from 

 which its history may be inferred with tole- 

 rable certainty. It is not only instinctively 

 led to seek the wheat plant as the natural 

 food for its young; but even to select the 

 vagina, or sheath of the lowest blade — rarely 

 the next contiguous one — for its nidus. Later 

 in the season, when the plant is in stalk, and 

 the lower leaves have decayed, we may some- 

 times find ihe larva, or pupa^ some distance 

 from the ground. In this way, the pupa 

 might be conveyed to a considerable distance, 

 even across the Atlantic. It sometimes affects 

 oiher grain, than wheat, such as barley, oats 

 and rye, perhaps timothy and some of the 

 other grasses ; but it is so seldom observed, ex- 

 cept in wheat, as to indicate necessity rather 

 than choice, in the selection of any other plant. 

 Say suggests that the female deposits the 

 egg in the sheath, by thrusting her elongated 

 oviduct between the blade and the stem, but 

 as the larva does not appear capable of mov- 

 ing, and is mostly found near the bottom of 

 the sheath, I think it more probable that she 

 pierces through the sheath, and places the 

 egg where we observe the larva. 



Some acute observers believe that the fly 

 is only produced at certain annual periods, 

 for example, the egg laid in the fall passes 

 through the larva state and becomes a pupa 

 before winter, in which condition it remains 

 till spring or early summer, when it escapes 

 a perfect fly, but does not deposit its eggs 

 until the next fall. However, this may ac- 



• In the foregoing specific description, copied from 

 Say, the wings are described "black;"— in all my spe- 

 cimens they are, ns 1 have described them, nearly color- 

 Ins and trajispareitt. 



cord with what is known of many other in- 

 sects, I think it is contrary to observation in 

 the present case. Sometimes when very few 

 insects can be found in the fall wheat, they 

 become quite numerous in the spring. I have 

 never seen the larvae in early spring — only 

 pupse — yet later in the season, larvae become 

 very common. The eggs of these were pro- 

 bably deposited by flies which proceeded from 

 the winter pupe. The spring larvae pass 

 through the pupa state, and become flies be- 

 tween the first and middle of the sixth month. 

 Without any observations on the insect, we 

 would naturally suppose the larva state more 

 destructive to the crop than the pupa, because 

 it then derives some nourishment from the 

 plant; yet, its greatest ravages are generally 

 in the spring. 



All the observations which I have been able 

 to make, have confirmed me in the opinion, 

 that they deposit their eggs at various sea- 

 sons of the year, subject to be influenced by 

 circumstances ; and that the duration of the 

 several stages of their existence, depends upon 

 season and temperature. In warm weather, 

 a few months, or even weeks, may be suffi- 

 cient to produce the fly from the egg; but 

 the progress of its metamorphoses will be 

 retarded, or entirely arrested by cold weather. 

 Last spring the flies were very numerous in 

 my wheat field when I sowed clover seed, ir 

 the beginning of the fourth month. Thej 

 could be seen to rise at almost every cast oi 

 seed, and would fly forward and settle dowr 

 again, in the same way as grasshoppers are 

 observed to do. These had, probably, com( 

 out of the winter pupae in the opening spring 

 and were about to deposit the eggs, which 

 after destroying the crop, produced other fliei 

 in the sixth month. This would allow a pe 

 riod of about two months for the completior 

 of their several changes. 



When the eggs are laid in early autumn 

 the insects will become pupte before winter 

 ready to emerge early in the spring and pre 

 pare for new devastations in the way I hav( 

 just mentioned. 



Observations are still wanting to determint 

 whether the larvfe of eggs laid later in thi 

 fall, can endure the winter in that state, o 

 whether the egg can remain and hatch in thi 

 spring. I think it probable, that neither thi 

 egg nor the larva can survive the frosts o 

 winter, unless protected from intense cold b} 

 a mantle of snow, as was the case in the win 

 ter of 1835-G. The autumnal prospect ex 

 ceeded any thing we had for a long tiin< 

 witnessed ; the dreadful reverse at the ensu 

 ing harvest, will be long remembered. Tht 

 fall was favorable to the growth of wheat, bii 

 it was also favorable to the propagation of it 

 greatest enemy — the fly. Its ravages wen 

 scarcely perceptible in the fall, yet it wai 



