44 HUMBLE CREATURES. 



lary palpi) attached to the maxillBe, and the second 

 {palpi labiales) connected with the lower hp. These 

 feelers enable the insect to test the nature of its food, 

 NoWj when an insect does not reduce its food by 

 mastication^ but, as in the case of the Fly and others, 

 obtains it by suction, aU the organs just enumerated 

 appear to be wanting, and a proboscis or suction- 

 pump is substituted, as being better adapted to the 

 changed character of the food on which the insect 

 subsists. On examining it more closely, however, we 

 find that the proboscis is, after all, but a transforma- 

 tion of the maxiUary organs just referred to as exist- 

 ing in the generality of insects. Let us take that of 

 the House-fly for example. The proboscis of the Ply 

 (PI. IV. fig. 1, c, and PI. V. fig. 1) consists of a tubu- 

 lar bag, formed of thin transparent membrane, which 

 arises from the front of the head, and is dilated at its 

 extremity, forming at this part a large sucking disc. 

 This bag is the converted portion of the lower lip 

 {labium), known as the ' ligula,' or tongue, a term 

 that is often applied to the proboscis itself, and is 

 furnished inside with a very complicated apparatus, 

 to enable it to perform its functions. The terminal 

 sucking disc (PI. V. fig. 1, a) is so constructed as to 

 gather the fluids and attract them towards an aper- 

 ture at b, which leads to the throat or gullet (to be 

 described hereafter) ; and in a groove on the under- 

 side of this tubular portion are two sharp bristles or 

 lancets, c, and beneath these, one more lancet, less 

 pointed, but still sharp {b). The apex of the latter is 



