INJURIOUS INSECTS. 247 



of an oblong-oval form ( Plate 5, fig. h ) , being broadest in the 

 middle and rounded at each end : it is slightly depressed, the under 

 side being considerably flattened ; thus in form considerably re- 

 sembling the leech when contracted. Its joints are indicated by 

 slight transverse impressed lines, by which it is divided into twelve 

 segments of about equal length. Sometimes a brownish cloud is 

 jjerceptible near the middle of the body on its under side, which is 

 ])robably caused by alimentary matter. If these worms are placed 

 for some days on a plate in a dry room, the outer skin of the body 

 becomes so dry and indurated that the worm is incapable of making 

 the slightest motion ; but on covering them with a wetted cloth, the 

 surface again in a short time becomes pliant and yielding ; and if 

 pressed with a needle, the animal writhes, and sometimes turns 

 itself over to escape from the annoyance. I doubt whether it ever 

 moults, or casts of! its skin, between its egg and its pupa state ; but 

 my observations have not been sufficiently exact and prolonged, to 

 speak positively upon this point. 



This is the form in which the insect passes the autumn and win- 

 ter. The accounts of writers disagree as to where the worm re- 

 mains during this period ; in fact few of them speak distinctly upon 

 this particular point. Mr. Kirby, however, describes the worm as 

 still continuing in the heads of the wheat ; but as a considerable 

 portion of them are missing, he thinks these have been destroyed 

 by parasitic enemies. He says, " I have seen more than once, seven 

 or eight florets in an ear inhabited by the (active) larvae, and as 

 many as thirty in a single floret, seldom less than eight or nine, and 

 yet I have scarcely found more than one pupa (dormant larva) in an 

 ear, and had to examine several to meet with that." Mr. Gorrie, on 

 the other hand, asserts that the maggots quit the ears of the wheat 

 by the first of August, and enter into the ground, where they re- 

 main through the winter. Mr. Shirrefl", also, from finding the fly much 

 more abundant in fields where wheat had been grown the preceding 

 year than it was in other fields, entertains the same opinion. Now 

 the truth is, Mr. Kirby and Mr. Gorrie are both right. A portion of 

 the larvae leave the grain before it is harvested, and descend to the 

 ground, where I have found them, under mouldy fragments of straw 

 on the surface, or buried a half inch or less within the soil. I thus 

 found them, common in the field already spoken of as examined on 

 the 16ih of June, a few days after the grain was harvested ; and 



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