LESSON 38.] 



NUTRITION IN INSECTS. 



133 



DIPTERA, 



isj two; pteron, a wing.) 

 HOUSE AND FLESH FLIES. 



FIG. 215. 



APTERA, 



(a, without ; pteron, a wing.) 



WINGLESS. 



613. The structure of the mouth of an insect gives fair induc- 

 tive evidence of the general conformation of the nutrimental organs, 

 as there is a necessary connection between them. 



614. The COLEOPTEROUS insects y or true beetles, whose delicate 

 wings are covered and protected by strong, bony sheaths, or wing- 

 covers, are mandibulate ; that is to say, their upper jaws, or man- 

 dibles, are well developed, and offer the best type of structure of these 

 organs. In the mouth of one of the predaceous and carnivorous 

 Tiger beetles (Cicindela hybrida), Fig. 216, is the well-formed, 

 slightly bilobed, upper lip (a) ; below, and on either side of it (b), 

 are the formidable upper jaws (mandibles), in this insect furnished 

 with a number of strongly formed teeth, the better to kill and divide 

 its living prey. 



The under portion of this- mouth is shown in Fig. 217. The un- 



FIG. 216. 



FIG. 217. 



Upper portion of the mouth of 

 Cincindela hybrida. 



Under portion of the mouth of Cicindela 

 hybrida. 



der jaws, maxillse (a), are furnished with two pairs of auxiliary 

 jointed appendages (6, c], which perform the function of hands in 

 conveying food to the mouth ; they are called palpi, or feelers, and 

 are supposed to be endowed with much sensibility. The trilobate 

 central piece (d) is the lower lip, to which is attached a long pair of 

 jointed feelers, beautifully fringed with hair(e) these are the labial 

 palpi (labium, the under lip), and the chin is shown at /. 



