528 



THYSANOPTERA 



CHAP. 



(Fig. 254) found on the left side of the body, as probably an enor- 

 mous development of the epipharynx. Previous to the appearance 



of Uzel's work, Garman had, however, 

 correctly described the structure of the 

 mouth; 1 he puts a different interpretation 

 on the parts ; he points out that the 

 mandibles (J\ so-called by Uzel, are at- 

 tached to the maxillae, and he considers 

 that they are really jointed, and that 

 they are lobes thereof; while the Mund- 

 stachel or piercer is, he considers, the 

 left mandible ; the corresponding struc- 

 ture of the other side being nearly 

 entirely absent. He points out that 

 the labrum and endocranium are also 

 asymmetrical. We think Garman's 

 view a reasonable one, and may re- 

 mark that dissimilarity of the man- 

 dibles of the t\vo sides is usual in 



FIG. 254. Face (with base of T , ,, ,, ,., , 



the antennae) of Aeoiothrips insects, and that the mandibles may 



fasdata. (After Uzel.) a, be hollow for Slicking, as IS shown bv 

 Labrum ; b, maxilla with its .. 



palp (c) ; bi, terminal part of the larvae ol Hemerobiides. There 



vertex near attachment of are usua U y three ocelli, but they are 

 mouth-parts ; a, membrane 



between maxilla and mentum ; absent in the entirely apterous forms. 



e, mentum ending in a point The wi appear to ; Spring from 



near / ; g, membrane ot 



attachment of the labial palp the dorsal surface of the body, not 



h ; i, ligula ; j, j the bristle- p f i cHrlp<* 



liU-fi mandihlPs- I' . t.h t.H,>Vp.r 11Om tlle S1( - le& 3 



anfprinr naiv IK 

 like mandibles ; k, the thicker ' P ai 



base of mandible ; I, chitin- always quite separated from the pos- 



ous lever ; m, mouth-spine. ,-\ -\ i -i 



with its thick basal part n, tenor 5 the wlll g s are always slender, 

 and o, its connection with sometimes very slender ; in other re- 



the forehead, r, r : v, for- , ., ., . , , , . , 



amen of muscle; s and t, spects they exhibit considerable variety ; 

 points of infolding of vertex ; sometimes the front pair are different 



, a prolongation of the . . . 



gena . in colour and consistence . irom tlie 



other pair. The abdomen has ten seg- 

 ments, the last of which is often tubular in form. The peculiar 

 vesicular structures by which the feet are terminated are, during 

 movement, alternately distended and emptied, and have two hooks 

 or claws on the sides. The stigmata are extremely peculiar, 

 there being four pairs, the first being the mesothoracic, 2nd 



1 Bull. Essex Inst. xxii. 1890, p. 24 ; also Amer. Natural, xxx. 1896, p. 591. 



