Platyptera 



^^3 



found, though in a reduced condition on the perfect 

 insects. The nymphs closely resemble their parents 

 in form ; they are most commonly found in swift 

 streams, and they feed on smaller water-insects, 

 such as Mayfly-grubs. The imagos are usually to 

 be observed near the water whence they came (lyo). 

 The Perlaria include only a single family — the 

 PerlicLv, with a world-wide distribution (3, II4, II5)' 

 By many naturalists they are regarded as a distinct 

 order — Plecoptera (96). 



ORDER 6.— THYSANOPTERA. 



Structure. — The Thysanoptera are a restricted 

 order of small insects 

 with elongate bodies, 

 jaws which serve for 

 suction with compara- 

 tively little modification, 

 and narrow, fringed 

 wings. The head is elon- 

 gate and flat with the 

 face sloping backwards ; 

 compound eyes are al- 

 ways present, and usually Fig. 100.—^. Umothrips dentkorms, 

 »U_„^ „:r.,.,1^ «,,^^ r.1^^ Hal., Europe. Magnified lo times. 



three simple eyes also. ^ j^^^, oi Poediothrips aibopkta, 



The feelers have from Uj:el. Magnified 16 times. «. epi- 



pharynx ; i^. ist maxilla ;/^. Its palp ; 

 six to nine cylindrical or c. 2nd maxilla;/^. its palp. After 



1 ji., ^ npi Uzel, " Monogr. Thysanoptera." 



beadlike segments. 1 he 



mandibles are needle-like piercers hidden in a conical 

 beak which is formed by the fusion of the upper lip 

 and the two pairs of maxillae, and lies in a cavity of 

 the prosternum ; the palps of both pairs of maxillae 

 are present, those of the first having two or three 

 segments, those of the second two or four. The 

 epipharynx is developed as a piercing stylet lying 



