THE AUCHENORRHYNCHOUS HOMOPTERA. 151 



peculiar punctured and rugulose appearance. I have made 

 further researches on the structure of an alcoholic example of 

 ^ Calyptoproctus stigma, Fabr., and found that the usual chitinous 

 skin of the femur at that place where the spots occurred was 

 darker than its environs, solid, and punctured in like manner, 

 and that the substance which formed the bri*,'ht spot situated on 

 the skin could be cut off as slices, and resembled chitin of a 

 peculiar loose and tolerably soft consistency. Tbis would in- 

 dicate that that spot is a peculiar organ, but its nature is quite 

 enigmatical to me. Spots of this nature are found in all the 

 Fulgoridae examined by me, and they are usually easily enough 

 discernible with a lens on dried specimens when the abdomen is 

 raised somewhat upwards, or the posterior femora turned some- 

 what downwards. The presence of this may be considered a good 

 family character. 



The posterior coxse are, as has been said, immovably fixed to 

 the metathorax, but the circumstance that the metasternum 

 nearest to it is entirely membranous, and that the extent of the 

 coalescence between the posterior coxse and metathorax is pro- 

 portionately somewhat short, allows, it would seem, a certain 

 elasticity. 



The largest and most powerful movement of the legs originates 

 from the articulation between the coxa and trochanter, and as 

 the insects — as is well known — can leap, one would expect to 

 meet with strange modifications of organization ; and one really 

 finds that there projects forward from the inner side of the tro- 

 chanter a powerful tendon (pi. ii. f. 7f) terniindting in an exceed- 

 ingly large, flat, plate-like bond (F), which receives the obliquely 

 forward and somewhat outwardly directed adductor muscle (which 

 is often visible through the metasternal articulation, and astonish- 

 ingly strong), the contraction of which certainly produces the 

 spring. (In the other saltatory Auchenorrhyncha, one finds, as 

 was to be expected, the same muscle with the tendon and its 

 dilatation, but not so powerfully developed.) The uncommonly 

 free movements between the trochanter and the femur may thus 

 surely enough, in part at least, both fill their usual role, and at 

 the same time compensate for the movements lost on account of 

 the firm fixation of the coxse, for the legs can, as a matter of fact, 

 serve for leaping and walking, or clambering upon plants, and 

 the movements of the femora in one single plan, resulting from 

 the fixed segment-axis in the articulation between the coxa and' 

 trochanter, are scarcely sufficient for these purposes. 



2. Tarsi. 



These are, as is well known, always trisegmentate, except in 

 a fewC'Stridulantia, where the number of segments is reduced 

 to two. The tarsi are always terminated by two equal claws, 

 which I have always found to be simple, without teeth or other 



