Bugs. Springtails. Earwigs. 123 



CHAPTER XXIII. 



ORDERS OF INSECTS. 



ORDER I. Rhynchota, This group consists of 



those insects which either undergo no metamorphoses 



or a very slight change in FIG. 7 o. 



the process of growth. 



Almost all have suc- 



torial mouths (fig. 70), 



consisting of a long tubu- 



lar labium, whose base is 



open or covered by the 



labrum like a little lid. 



The mandibles and 



maxillae are altered into 



piercers or bristles which 



work within the tube. A 



few, however, like the 



bird-lice, have hook-like 



mandibles and chewing 



mouths. Many of the 

 insects of this order are 

 parasites on animals and 



Mouth of Bug. 



Showing the median elongated labium, 

 the four bristle-like styles on the 

 mandibles and maxillae, also, at the 

 sides, the antennae and eyes. 



wingless, as lice and bugs ; others, the aphides, the 

 small green insects which are so abundant on roses, 

 geraniums, &c., are plant parasites, and often winged. 

 These aphides are marvellously prolific, a single 

 pair being capable in one year of producing a progeny 

 of twenty thousand millions or even more. Some 

 aphides have glandular tubes on the abdomen which 

 secrete a sweet honey- like fluid. This fluid is used 



