LESSON 41.] 



NUTRITION IN INSECTS. 



145 



Under part of mouth of Dragon fly. 



closing the mouth (c) of great power. The antagonist muscle (d) is 

 simply required to open the mouth, and it is slight accordingly. The 

 under jaws (Fig. 239) are short, and not very powerful (a) ; each is 

 supplied with a small feeler (/), or palpus. 



649. These organs are chiefly FIG. 289. 

 used as hands, to hold a living in- 

 sect while the upper jaws kill and 



divide it, and afterwards convey 

 the pieces to the mouth. 



650. The under lip (b) is un- 

 usually large, provided with two 

 processes with hinge joints, by 

 means of which they can either be 

 extended or remain closed ; this 



apparatus forms a table, or platform, on which an insect can be 

 placed while the upper jaws act upon it. Such an arrangement was 

 necessary for an insect who kills and eats its j rey on the wing. The 

 mentum, or chin, is shown at c. 



651. In the Hymenoptera, the mouth has undergone remarkable 

 modification, especially in the Bees. These insects require strong, 

 toothed jaws, for manifold purposes, and con- 

 sequently their mandibles are constructed upon 



this type (Fig. 240, a). The upper lip is 

 shown at f. But the great business of their 

 lives is to procure the nectar from flowers, and 

 convert it into honey, and for this purpose an 

 especial apparatus is necessary. To this end, 

 the under jaws, and their dependences (palpi), 

 have become strangely metamorphosed; the 

 under jaws (b) are formed into a tube to re- 

 ceive and protect the rest of the mouth when 

 not required for use. "Within these (d, d) are 

 two long, jointed organs, gradually tapering 

 upwards, with short terminal processes nearly 

 at right angles ; these are the maxillary palpi, 

 or feelers of the under jaws. Their function appears to be that of 

 hands, to hold back the petals of a flower, whilst the long central 

 tongue (e) is busily engaged lapping up the nectar; for this purpose 

 they appear to be admirably adapted. The tongue (e) is much long- 

 er when extended than any other part of the mouth ; it is perforated 

 at its extremity, and has in its interior a canal, which is a continua- 

 10 



FIG. 240. 



Mouth of the honey bee, 

 Apis melliflca. 



