598 DIPTERA. 



transformations. Moreover, the pupa is entirely naked, not 

 being enclosed either in a cocoon or in the puparium formed 

 of this outer skin of the larva, and it has its limbs and wings 

 free or unconfined. The pupa state lasts but a short time, 

 a week or two iit most, and probably, in many cases, only 

 a few days. Under the most favorable circumstances, the 

 pupa works its way to the surface, before liberating the 

 included fly ; and when the insect has taken wing, its empty 

 pupa-skin will be seen sticking out of the ground. In other 

 cases, the fly issues from its pupa-skin in the earth, and 

 comes to the surface with flabby wings, which soon expand 

 and dry on exposure to the air. This last change occurs 

 mostly during the months of June and July, when great 

 numbers of the flies have been seen, apparently coming from 

 the ground, in fields where grain was raised the year before. 

 Some persons have stated that the insects are transformed 

 to flies in the ears of the grain, having probably mistaken 

 the cast-skins of the maggots found therein for the shells 

 of the chrysalis or pupa. 



Several cases of the efficacy of fumigation in preventing 

 the depredations of these insects are recorded in our agricul- 

 tural papers.* For this purpose brimstone has been used, 

 in the proportion of one pound to every bushel of seed sown. 

 Strips of woollen cloth, dipped in melted brimstone, and 

 fastened to sticks in different parts of the field, and particu- 

 larly on the windward side, are set on fire, for several 

 evenings in succession, at the time when the grain is in 

 blossom ; the smoke and fiimes thus penetrate the standing 

 grain, and prove very offensive or destructive to the flies, 

 which are laying their eggs. A thick smoke from heaps 

 of burning weeds, sprinkled with brimstone, around the 

 sides of the field, has also been recommended. Lime or 

 ashes, strown over the grain when in blossom, has, in some 

 cases, appeared to protect the crop ; and the Rev. Henry 

 Colman, the Commissioner for the Agricultural Survey of 



* Among others, see The Cultivator, Vol. V. p. 136. 



