BULLETIN 39, UNITED STATES NATIONAL MUSEUM. 



[18] 



6 



Fig. 20.— a Tree-hop- 

 per (Ceresa hubalus). a, 

 side ; 6, top view. 



from two pores, situated ou the under side of the metathorax. Such 

 well-known insects as the Bed-bug and Chinch-bug 

 belong- here. The habits of the species are varied, 

 and while some are beneficial, others are quite injuri- 

 ous to man. 



"The Whole-winged Bugs (Figs. 20 and 21), on the 

 contrary, are all plant-feeders, and with the excep- 

 tion of a few, such as the Cochineal and Lac insects, 

 are injurious. The secretion of a white, or bluish, 

 waxy, or farinose substance from the surface of the body is as charac- 

 teristic of this section as the 

 nauseous odor is of the first. 

 It forms three natural divi- 

 sions, arranged according to 

 the number of joints to the 

 tarsi — namely Trimera, with 

 three joints; Dimee A, with 

 two joints, and Monomera, 

 with one joint to the tarsi." 



Suborder Thysanoptera -^ ^-^s:^- 



{duqavoq^ a fringe; itrepuv^ TV 



wmg) : This suborder con- ^ ^^Xt^ 

 tains the single family Thri- ^ ^ 



. . Fis. 21. — A Plant-louse ((ScHxoweitraZcMiig'era). a, infested 



J)t^tfe, which comprises minute root; ^ larva; c, ringed insect; d-(j, parts of perfect 



insects commonly known as insect enlarged. 



Thrips, and of which a common species, Tlirips striatiis, is shown in 

 the accompanying figure. (See Fig. 22.) They bear strong relations 

 to both the Pseudoneuroptera and the Hemiptera and by later writ- 

 ers are generally associated with the latter order. They feed on plants, 

 puncturing and killing the leaves, or on other plant-feeding species of 

 their own class, and are characterized by having narrow wings crossed 



ou the back when at rest, and 

 beautifully fringed, from which lat- 

 ter feature the name of the suborder 

 is derived. 



The month parts are peculiar in 

 that they are intermediate in form 

 between the sucking beak of He- 

 miptera and the biting mouth parts 

 of other insects. 



Their eggs resemble those of 

 Hemiptera; the larvse and pupae 

 are active, and in form resemble 

 the adult, except in the absence of wings. Some species, also, are wing- 

 less in the adult stage. 



Fig. 22.~Thrips striatus, with wings enlarged 

 at side. 



