342 



COLLEGE ZOOLOGY 



and consequently weak 

 and thin. Chickens take 

 dust baths to rid them- 

 selves of Menopon pal- 

 lidum (Fig. 266), the most 

 common species. 



Order 8. Thysanop- 

 tera. THRIPS (Fig. 267). 

 -Insects with four 

 narrow, membranous 

 wings fringed with long 

 hairs; mouth-parts inter- 

 mediate ; the metamor- 



phosis transitional, not 

 FIG. 267. Order THYSANOPTERA. Pear r 



thrips, Euthrips pyri. (From Moulton, Bui. Complete, but a quiescent 

 80, Bur. Ent., U. S. Dept. Agric.) Stage OCCUrS. 



The feet of these insects are without claws, their place being 

 taken by bladders adapted for clinging to 

 leaves or flowers. The males are not com- 

 mon, since parthenogenesis is the usual 

 method of reproduction. Several species 

 are distinct pests; these are the onion- thrips 

 (Thrips tabaci), the wheat- thrips (Euthrips 

 tritici), the grass- thrips (Anaphothrips stri- 

 atus), and the fruit thrips (Euthrips pyri) 

 (Fig. 267). 



Order 9. Euplexoptera. EARWIGS (Fig. 

 268). Insects usually with four wings; 

 fore-wings leathery, small, and veinless; 

 biting mouth-parts; posterior end of ab- 

 domen bears pair of forceps; metamorphosis 

 incomplete. 



This order contains the family FORFI- 

 CULID^. The earwigs are not common in 

 North America. They feed at night on fruit port.) 



FIG 268 . _ Ord er 

 EUPLEXOPTERA. Ear- 



