DIPTERA. 79 



battering of the fly's head, and the insect at length comes out 

 triumphant. This fly, which should be blue, is then grey ; it, how- 

 ever, comes quickly to perfection, at the end of three hours attaining 

 its ultimate colour ; and in a very short space of time every part 

 of the animal becomes of that firmness and consistency which 

 characterises them. At the same time, the wings, which at the 

 moment it came into the world were only stumps, extend and unfold 

 themselves by degrees. The meat-fly is represented below (Fig. 55). 

 One of the features in the formation of this fly which most 

 attracted the attention of Reau- 

 mur, and which is likely to excite 

 the curiosity of all those who 

 take an interest in insects, is the 

 composition of its trunk. We 

 will, therefore, with that illus- 

 trious observer, take a glimpse 

 at the remarkable and compli- 

 cated apparatus by the aid of 

 which the fly can suck up 

 liquids, and can even taste solid 



and Crystalline Substances, SUCh Blue-bottle fly (Callipforl \,omitona\ magnified. 



as sugar. 



It is no difficult matter to make a fly show its trunk extended to 

 its full extent. One has only to press between the finger and thumb 

 either the two sides of the upper and under part of the thorax. It is 

 thus forced at once to put out its tongue. 



The trunk appears to be composed of two parts joined together, 

 and forming a more or less obtuse angle (Fig. 56). The first portion 



Fig 56. Trunk of the Meat-fly. Fig 37. Conical part of the trunk. 



of the trunk, that which joins the head, is perfectly membranous and 

 in the form of a funnel. We will call it the conical part, and show it 

 separately (Fig. 57). The second portion terminates in a thick mass, 

 in part cartilaginous or scaly, and of a shiny brown colour. Above 



