136 MISS STAVELEY ON THE NEURATION 



the Museum collection, tliougli I do not find it mentioned in the descriptions of that author. 

 I may also observe that it is not represented in any of the 370 very much enlarged draw- 

 ings of the species of this genus engraved in Koch's ' die Pflanzenlause, Aphiden, getreu 

 nach dem Leben abgeleitet und beschrieben.' Nor are they mentioned in the work of 

 MM. Amyot and Serville, ' Hist. Nat., Hemipteres,' Paris, 1843. 



The wing of Aphis is figured with a group of hooks, in a paper liy Mr. John Tyrrell, in 

 the ' Jom-nal of Microscopical Science,' vol. iii. p. 230. This does not agree with any- 

 thing that I have seen, nor does his third figure, which represents the fore and hind 

 wings as joined casta to costa. 



In all the species of Aphides that I have examined, there is only a single hook placed 

 near the middle of the front edge of the hinder wing ; and the hinder edge of the front 

 wing is turned up for a considerable distance to receive it. 



In general the hook is simple, subcylindricsll, tapering to a point, with an enlarged 

 base ; but in one or two species it looks as if it were compressed or flattened, and is 

 slightly striated longitudinally. 



It is not to be observed in the wings of JLivia, Psyllce, or any of the neighbouring genera 

 Homoptera which have come under my observation. In most of the other genera of this 

 order of insects, the fore wings are more coriaceous or horny than in Aphis, and are to be 

 regarded as much in the light of covers to the other wings as organs of flight. 



In some Lepidopterous insects there is an appendage thus described by Mr.Westwood :— 

 " Another peculiarity consists in the apparatus by which the two wings on the same side 

 are retained together in the same line during flight, composed of a loop in -n^hich a strong 

 bristle plays (fig. 102. 8), The loop is formed either by an elevated portion of the mem- 

 brane of the strong central vein of the upper wing on its under surface, or by a tuft of 

 raised hairs. This appears to have been first noticed by De Geer (torn. i. tab. 10. f 4) and 

 Harris (in his Essay upon the membrane of the wings), and afterwards by Giorna (Lin. 

 Trans., vol. i. p. 135) in greater detail. M. Poey (Ann. Soc. Ent. Prance, tom. i.) has 

 observed that the bristle is simple in the males but multiplied in the other sex, in which, 

 according to Kirby and Spence, there is no annulus, and consequently these individuals 

 are less fitted for flight. See also Hoeven in Perussac's Bui. Sci. Nat., March, 1828. It 

 is chiefly among the Spingidce and Moths that we find this apparatus, the butterflies being 

 destitute of it." (' Modern Class, of Insects,' vol. ii. p. 317.) And he adds as a foot-note 

 at page 332 : " Prom the observation of Mr. Haworth (Lep. Brit. p. 19) upon the strong 

 flight of the males of the Purple Emperor {Apatura Iris), it Avould appear that the males 

 of that species possess this socket and spring, as he terms this apparatus, and of which 

 the females, which fly but little, are destitute." 



represent the hook on the wing in any, although his figures of A. platanoides and A. piniphila are of a large size. He 

 has observed and figured the hooks on the hind wing of the genus Ghernies in two species, viz., Chermes coccineus 

 (t. 12. f. 1. o. 9), Chermes laricis (t. 13. f. 5). 



" Mr. Curtis, in vol. xi. of the ' British Entomology,' divides the Aphides into two genera, and figures as the types 

 Cynara roboris (p. 576), Aphis tiliee (p. 577). He does not describe the hooks in his generic characters, nor represent 

 them in his figures : this is the more remarkable, as he figures the hind and fore wings of Cynara roboris in the rela- 

 tive position, of an enlarged size, to show the nerves." 



