332 Transactions of the [Sess. 



and a blunt point, there being from 3000 to 4000 of these little forks 

 on the lobes of the Blow-fly. The trachefe spring from two ciirved 

 chitinous plates, situated at the entrance to the mouth, and for 

 some little distance from their attachment the rings are not bifur- 

 cated ; and as the rings approach the extreme margin of the lobes, 

 they become closed. Springing from the same chitinous plates are 

 the teeth, variously estimated at from forty to sixty in number, 

 bifurcated at their free ends. When the lobes are closed, the teeth 

 rest between the false trachea3 ; and when the lobes are quickly 

 opened, the teeth spring forward, and in this way, in my opinion, 

 act like so many little chisels. The opening of the lobes is effected 

 by two powerful chitinous bands or muscles ; and I would hint that 

 a good rack-adjustment to the microscope is almost a necessity if 

 one wishes to follow closely the nimble movements of the proboscis. 

 I may mention that this object, as prepared by professional mount- 

 ers, is only useful for showing the false trachefe. As a rule, the 

 teeth are too much flattened, and the chitinous plates that support 

 the teeth and tracheas are broken at the base, and turned over so 

 that it is almost impossible to form anything like a correct idea of 

 the relation of the different parts. 



In the tongue of the Blow-fly, then, with its false tracheae and 

 teeth, we find an admirable arrangement for scraping and chisel- 

 ing ; and that it is used for this purpose I think I can almost 

 prove, for under the microscope I have placed a piece of sugar, 

 through which a hole was eaten by the fly, while lying on the 

 stage of the microscope. The sugar was hard and crystallised, 

 and too large to be covered by the open lobes, yet it was never 

 allowed to fall ; and as the work of scraping and chiseling went 

 on, the proboscis gradually disappeared in the sugar, and finally 

 emerged on the other side, leaving the sugar like a ring on the 

 trunk of the fly ; and there are, besides, certain minute points left 

 by the action of the tracheae which I think could hardly have re- 

 mained had the saliva been the active solvent and sole agent in 

 the consumption of the sugar. It is curious to note how observers 

 differ. Mr Lowne says, " No solid food is taken by the fly ; " while 

 Mr Suffolk, an equally accurate observer, informs us, " I have fre- 

 quently used raw meat as food for my flies, and have found it 

 eaten freely." Now we all know how partial the Blow-fly seems to 

 be to a tender roast or a leg of mutton ; yet when placed on the 

 stage of the microscope in the way described, neither coaxing nor 

 starving would induce the fly to touch a piece of meat. This refusal 

 is quite in keeping with what we know of the false tracheae, whose 

 sharp and pointed forks are totally unfitted to cope with a soft and 

 yielding substance like flesh ; and as the teeth cannot be made to 

 oppose one another, they are ahke useless for this purpose. The fly 

 is content to sip the exuded juice, but cannot be said to eat meat 



