( 230 ) 

 NOTES AND CORRESPONDENCE. 



Feet and "Wings of Insects. — In confirmation of the opinion 

 of Mr, Hepworth and other naturalists, that the use of the 

 cushions beset with hairs terminating in glands secreting a 

 glutinous substance, is to attach the foot to what it walks on 

 by means of such secretion, and not by suction, I would 

 suggest that the hooks on the feet of flies are intended not to 

 attach the fly to anything, but to be used as fulcrums (fulcra, 

 Mr. Editor, " if you think it better English," as Lord Plunket 

 said when corrected for using the word memorandums), or 

 props which the fly can push against when it wishes to detach 

 the cushions. Without these hook-shaped props, the fly, 

 when once stuck fast, must remain so. 



Some Hymenoptera, Messrs. Kirby and Spence state, have 

 booklets on their wings. These are used to attach one wing 

 to the adjoining wing during the insect's flight. My observa- 

 tion leads me to think that these hooks are a distinguishing 

 characteristic of all Hymenoptera ; but I throw out the sugges- 

 tion for the investigation of naturalists. The hooks vary 

 very much in number. In some minute Hymenoptera, we find 

 but three, while on the wasp I think there are twenty-four, 

 and on the hornet, twenty-eight. They are invariably on the 

 smaller wing, and the margin of the other is folded back, and 

 thickened at the edge to give the hooks a firm hold of it. 



So far as my experience goes, these hooks are confined to 

 the Hymenoptera, with but one exception — the aphis. Every 

 aphis possesses one or more hooks on the smaller wing for the 

 same purpose of attachment ; but while in the Hymenoptera, 

 they are arranged separately along the margin of the wing, 

 in the aphis, on the other hand, the hooks, however numerous, 

 spring from one point, or at least are placed as closely as 

 possible together. The number of hooks differs, in the different 

 varieties of aphis that I have examined, from one to seven. 



An aphis found on the Box and on the Hawthorn appeared 

 at first to have none, but after a careful inspection, the hook 

 was found of a different shape from what is usual, inserted in 

 the wing not quite at the edge, and standing out perpendicular 

 to the plane of the wing. The Box- and the Hawthorn- aphis 

 have this further peculiarity, that to compensate for the absence 

 of hooks in their usual position, they have a row of hooks 

 near the insertion of the wing in the insect's body, and the 

 larger wing has a corresponding fold at the same place to re- 

 ceive them. — John Tyrrell, Newcourt. 



