396 FOOD OF INSECTS. 



and more resembling the proboscis of an elephant, and 

 terminates in two turgid liplets : and the accompanying 

 lancets are themselves included in ;an upper hollow case, 

 in connexion with which they probably compose an air- 

 tight tube for suction. The number and form of these 

 instruments is extremely various. In some genera (Mus- 

 ca) there is but one, which resembles a sharp lancet. 

 Others (Empis, Asilus,} have three, the two lateral ones 

 needle-shaped, that in the middle like a scymetar; to- 

 gether forming so keen an apparatus, that De Geer has 

 seen an Asilus pierce with it the elytra of a lady-bird ; 

 and I have myself caught them with not only an Elater 

 and weevil, but even a Hister in their mouths. In many 

 horse-flies we find four ; two precisely resembling lancets, 

 and two, even to the very handles, buck-hafted carving- 

 knives*. The blood-thirsty gnat has five, some acutely 

 lanced at the extremity, and others serrated on one side. 

 The flea, the spider, the scorpion have all instruments 

 for taking their food of a construction altogether differ- 

 ent 5 . But it is impossible here to attempt even a sketch 

 of the variations in these organs which take place in the 

 apterous genera, and in many of the dipterous larvae. 

 Suffice it to say that they all manifest the most consum- 

 mate skill in their adaptation to the purposes of the in- 

 sects which are provided with them, and which can often 

 employ them not only as instruments for preparing food, 

 but as weapons of offence and defence, as tools in the 

 building of their nests, and even as feet. 



Some insects in their perfect state, though furnished 

 with organs of feeding, make no use of them, and con- 

 sume no food whatever. Of this description are the 

 PLATE VII. FIG. 5. b PLATE VII. FIG. 8. 10. 



