8O THE INSECT WORLD. 



the conical portion are two oblong antennae, without joints, of 

 chestnut colour, and 'furnished with hairs. 



On ceasing to press the thorax, the membranous conical portion 

 may be seen to draw itself back within its sheath (Fig. 58). The 

 second portion is at the same time drawn into the cavity, but it 

 raises itself by forming a more and more acute angle, so that when 

 it reaches the opening of the cell it is parallel with, and its length is 

 equal to that of the cell, which is quite large enough to receive it. 

 The base lengthens and flattens a little, and conceals the trunk. 



Let us cause the trunk to extend itself a second time, in order to 

 observe its tip minutely. Here the opening is placed, which may be 

 looked upon as the mouth of the insect, and is provided with two 

 large thick lips (Fig. 59). These lips form a disc, perpendicular to 



Retractile proboscis of Blue-bottle fly. Extremity on the'proboscis of a fly. 



the axis of the trunk ; the disc is oval, and is divided into two equal 

 and similar parts by a slit. The lips have each a considerable num- 

 ber of parallel channels situated perpendicularly to the slit. These 

 channels are formed by a succession of vessels placed near each 

 other. On pressing the trunk we see that these vessels are dis- 

 tended by a liquid. Reaumur, from whom we borrow these details, 

 discovered a few of the uses to which this trunk is applied. He 

 covered the interior of a transparent glass vase with a light coat of 

 thick syrup. He then put in some flies, when it was easy to see 

 some of them proceed to fix themselves to the sides of the vase, and 

 regale themselves on the sugary liquid, of which they are very fond. 

 He observed them carefully, and in his admirable work he recom- 

 mends those who are curious to try the experiment, with which, like 

 himself, they will certainly be satisfied. 



While the body of the trunk is stationary its end is much 

 agitated. It may be seen to move in different ways, and with an 

 astonishing quickness ; the lips acting in a hundred different ways, 

 and always with great rapidity. The small diameter of the disc 



