482 INSECTA. 



neck along the thorax, and, when got into the abdomen, it dilates into 

 a pretty large bag of a particular shape, swelling out laterally, having 

 the long axis across the abdomen. The other canal passes down behind 

 the before described, and along with it into the belly, then becomes 

 larger, which increase of size may be called ' stomach ; ' and which again 

 becomes smaller, forming ' intestine.' This is soon thrown into close 

 convolutions, and then becomes a more straight canal, into which enter 

 the ducts, which I suppose to be either liver or pancreas. Where it 

 commences rectum there is a valvular structure, and then a swell 

 forming a kind of reservoir for the faeces, in which there is a particular 

 appearance or structure. It is there flat, more firm in texture, and has 

 two lateral conical bodies on each side, whose base adheres to the side of 

 the gut 1 ; and the whole body projects into the cavity of the gut 

 obliquely downwards. Into the base passes a dark vessel, which is an 

 air-vessel. We may suppose these so many glands opening at the apex 

 into the gut. Then the gut becomes small, and terminates at the anus 

 behind, or rather above the vagina. 



The bag belonging to the first-described canal [oesophagus] is to be 

 considered as a craw or crop, viz. a reservoir for the food, to be ready 

 for digestion ; and, as the abdomen contains almost every internal part 

 of the animal, it is obliged to be situated in this cavity ; but why it did 

 not communicate with the oesophagus, or true stomach lower down, I 

 do not know. That it is a reservoir for food I proved by experiment. 

 I kept some of these flies fasting for some time. I then gave them milk, 

 which they drank readily ; and when I thought they had filled their 

 bellies, I put them into spirits, which assisted in coagulating the milk 

 wherever it might be. 



On opening the abdomen, I found this bag full of curd and whey, as 

 also some in the stomach. That I might be still more certain that this 

 bag was reservoir only, that it had no other business in digestion, and 

 therefore that food would be taken into the stomach immediately, if 

 immediately wanted, I repeated the above experiment with this differ- 

 ence. The milk was now coloured with cochineal. I not only found 

 the bag full, but the stomach and intestines, so that the food when 

 wanted was immediately carried into the stomach. 



I kept a fly for twelve hours without food, and then gave it milk and 

 killed it : I found no milk in the crop, but it had got through almost 

 the whole tract of the intestine. Here the animal had immediate 

 occasion for it ; therefore it did not go into the crop. This experiment 

 at the same time shows that, probably, every part of the intestine digests, 



i [Hunt. Prep. Phys. Series, No. 2123.] 



