82 THE INSECT WORLD. 



means the fly employs with sugar. When the trunk is forced to act 

 upon a grain of irregular and rugged form, on which it cannot easily 

 fasten, its end distorts itself to seize and hold it. It is sometimes 

 very amusing to see how the fly turns over the grain of sugar in 

 different ways ; it appears to play with it as a monkey would with 

 an apple. It is, however, only that it may hold it well in order to 

 moisten it more successfully, and afterwards to pump up the water 

 which has partly dissolved it." 



Re'aumur often observed a drop of water at the end of the trunks 

 of flies which were perfectly surfeited with food. This drop ascended 

 the trunk, then re-descended to the end, and this many times in suc- 

 cession. It appeared to him that it was necessary for these insects, 

 as for many quadrupeds, to chew the cud, as it were ; that, in order 

 the better to digest the liquid they had passed into their stomachs, 

 they were obliged to bring it back into the trunk that it might return 

 again better prepared. 



In order to assure himself directly of the reality of his supposition, 

 Reaumur tested the water which a fly, that he says " had got drunk 

 on sugar," had brought back to the end of its trunk ; he found this 

 to be sugar and water. Also, having given a fly currant-jelly, he 

 observed, after it had sufficiently gorged itself, several drops of red 

 liquid in its trunk, and having tasted it, found it had the flavour 

 which, from its appearance, he guessed it would have. 



The illustrious observer, who had already made all these dis- 

 coveries on the formation and functions of the trunks of insects, often 

 reflected on the fact that the liquors of which flies are most fond are 

 enclosed under the skin of certain fruits, such as pears, plums, grapes, 

 &c., or even under the skin of some animals of which they suck the 

 blood. In order that the trunk of a fly may act under such circum- 

 stances, it is necessary for it to pierce and open the skin. If this is 

 the case, flies ought to be possessed of a lancet. He looked a long 

 time for this lancet, and at last found it. It is situated on the upper 

 side of the part of the trunk which is terminated by the lips ; it is 

 placed in a fleshy groove, and is enclosed in a case. It has a very 

 line point, and is of light colour (Fig. 61). The point is situated in 

 the opening which is to be seen between the lips of the trunk, at its 

 anterior end, through which liquids may pass. That is the only 

 opening of the lips ; and the sucker which takes up the liquid is the 

 same part which we just now called the case of the lancet. 



Reaumur is so interesting an author that it is difficult to cease 

 quoting him ; but we must continue our review of the principal kinds 

 of Diptera. 



