428 INSECTS INJURIOUS TO VEGETATION. 



safely lodged in its bed on the side of the stem, near the root of 

 the plant, and protected from the cold by the dead leaves. To- 

 wards the end of April and in the forepart of May, or as soon 

 as the weather becomes warm enough in the spring, the insects 

 are transformed to flies. They make their escape from their 

 winter quarters by breaking through one end of their shells and 

 the remains of the leaves around them. In the " Observations 

 on the Hessian fly," written by Jonathan N. Havens, Esq., and 

 published in the first volume of the " Transactions of the So- 

 ciety for the Promotion of Agriculture, Arts, and Manufactures 

 in New York," it^ is stated, that " whenever the fly has been 

 hatched in the house, it always comes forth from its brown case, 

 wrapt in a thin white skin, which it soon "breaks, and is then at 

 liberty " ; and Mr. Havens supposes, that the same thing occurs 

 when the transformation takes place abroad. Nothing of the 

 kind, however, has been recorded by any other writer on this in- 

 sect. Very soon after the flies come forth in the spring, they 

 are prepared to lay their eggs on the leaves of the wheat sown in 

 the autumn before, and also on the spring-sown wheat, that be- 

 gins, at this time, to appear above the surface of the ground. 

 They continue to come forth and lay their eggs for the space of 

 three weeks, after which they entirely disappear from the fields. 

 The maggots, hatched from these eggs, pass along the stems of 

 the wheat, nearly to the roots, become stationary, and turn to 

 puppe in June and July. In this state they are found at the time 

 of harvest, and, when the grain is gathered, they remain in the 

 stubble in the fields. To this, however, as Mr. Havens remarks, 

 there are some exceptions ; for a few of the insects do not pass 

 so far down the side of the stems as to be out of the way of the 

 sickle when the grain is reaped, and consequently will be gath- 

 ered and carried away with"^ the straw. Most of them are trans- 

 formed to flies in the autumn, but others remain unchanged in the 

 stubble or straw till the next spring. Hereby, says Mr. Havens, 

 " it appears evident, that they may be removed from their natural 

 situation in the field, and be kept alive long enough to be car- 

 ried across the Atlantic ; from which circumstance it is possible 

 that they might have been imported " in straw from a foreign 

 country. In the winged state, these flies, or more properly 



