The Scottish Naturalist. 65 



The anterior end of the miner is tapered to a fine point, like 

 that of the maggot of the flesh-fly, and is provided with two 

 hard black hooks, bent downwards, which supply the weapon 

 by which it separates the cuticle, and triturates the parenchyma 

 into a pulp suitable for deglutition. These appear to be put 

 into exercise by the repeated movements to and fro of the head; 

 and the leaf by their means is literally flayed, in the same 

 manner as the hide of an animal is detached by the knife of the 

 butcher. If the body is watched while the maggot is at 

 work, there is observable a continued equal moving backwards 

 and forwards, like a reiterated pulsation, which may facilitate 

 the transmission of the food through the simple alimentary 

 passages. One, taken out of its chamber, felt little difficulty in 

 selecting a new residence, and soon again put itself under 

 cover. With little restraint upon their voracity, from the ample 

 scope afforded, these maggots when in large assemblages of 

 from eight to a dozen (from four to six is a common number) 

 will consume the substance of about one fourth of the upper 

 layer of a leaf during a day ; and although I have not attended 

 to their proceedings from the commencement, they unquestion- 

 ably, from their almost unintermitted exertions, attain a rapid 

 development. In the fields I find the fly about the end of 

 May, and in some seasons I observe that the docks are affected 

 with the young maggots about the 2nd or 3rd of June. Those 

 I had under my observation were obtained on the 6th of July ; 

 and were placed in a tumbler inserted over a flower-pot con- 

 taining soil. Most of them had buried themselves in the earth 

 before the 17th, having been pretty well full-fed previous to my 

 confining them. The first fly appeared on the 6th of August ; 

 two came out on the 7th ; and others in succession. This 

 brood gives rise to a second race of maggots, which continue 

 to feed till winter closes in when they betake themselves to 

 their brumal retreat, are converted into pupae, and eventually 

 in spring, when the season admits, become the progenitors of 

 an issue as numerous as the first. Several of the flies, however, 

 were not so speedy in making their exit, but remained in the 

 pupa state, till the time of their vernal revivescence. This was 

 about the 7th of May in the ensuing season. Those that came 

 forth in August, and in the early part of next season, were 

 chiefly males ; the females were later in arriving at the perfect 



