THE FLY. 45 



pierced by an opening, as above mentioned, tbat 

 passes up its centre and conducts to the gullet, which 

 runs through the base of the tubular bag. These 

 lancets are the representatives of the 'niaxill«' and 

 'mandibles,' and are employed to puncture the ob- 

 jects from which the Fly sucks the juices. On the 

 under surface of the disc are a number of lines run- 

 ning from the circumference to the centre, as in 

 PL V. fig. l,dd; and when these are highly magnified, 

 they are found to be a number of ribs, forming about 

 three-fourths of a tube, the open portion of which 

 faces downwards, so as to admit the liquid foodj 

 when the fluid has entered it passes along, probably 

 by capillary attraction, to the centre, close around 

 which aU the tubes open. Here it enters the aper- 

 ture in the siagle lancet, finally to reach the gullet. 

 These ribbed tubes are connected together by very 

 dehcate lines, spriagiag from the poiats of the ribs, 

 as represented in PL V. fig. 3. Besides the piercers, 

 the proboscis is furnished with a pair of well-defined 

 maxillary palpi (PL V. fig. 1, e), which enable it to 

 test the character of its nutriment ; and the entire 

 apparatus is covered with a great number of fine hairs, 

 and permeated by respiratory tubes [trachea), the 

 nature of which we shall consider hereafter. 



You may, perhaps, not have been aware that the 

 harmless little Fly possesses such weapons as the 

 aforesaid lancets ; but if you have ever been stung by 

 one about the time when they are dying out, and have 

 seen the drop of blood arising from the wound, you 



