NATURAL HISTORY SOCIETY OF GLASGOW. 313 



species, taken in Spitzbergen by the Rev. A. E. Eaton, which is 

 much smaller than the usual form, more hairy, and with the 

 posterior tibiae and tarsi devoid of black. It was, I believe, taken 

 on willows, and the thorax was dusted over with pollen. This 

 variety I propose to call palliditarsiis. 



Nematus crassulus, Dahlbom. 



Nematus crassulus, Dahlbom, Conspectus, No. 96 ; Thomson, 

 Hymen. Scand., i., 157, 90 ; i\^. leucosiictus, Hartig, Blatt. und 

 Holzw., 202, 33 (forte); A^. xanthogaster, Foerster, Verb. pr. 

 Rheinl., 1854, p. 315 (forte); Kaltenbach, Die Pfianzenfeinde, 

 580 (forte). 



As the account of the habits of this insect given by Kaltenbach 

 (the only author who has described the larva), is not very minute, 

 I think that a description of its life- history ma}^ be of interest, 

 more especially as the species has never been mentioned in any 

 works relating to British entomology. 



If we go out to Fossil marsh about the beginning of July, and 

 examine the leaves of Salix viminalis and other willows growing 

 there, we shall find that some of them have the edges neatly 

 turned down on the underside, indifferently on the right or left, 

 and (as a rule) extending down the whole length, just in the same 

 way as we ourselves turn down the edges of the leaves of a book. 

 Usually there is only one side turned down, but occasionally both 

 are treated in this fashion. If w^e open the fold and examine it 

 carefully, at one end there will be observed a minute oval e^g, 

 embedded in the epidermis. This is the egg of N. crassulus. 



It may be asked — How, and by what is the leaf folded down 1 

 Certainly not by the insect during its larval life, as is usually the 

 case with leaf-rollers, for with this species the leaf is folded down 

 before the larva makes its appearance ; so it is clear that tlie work 

 must be done by the perfect insect. But how the fly manages to 

 perform the operation, is a question that I cannot at present 

 answer, not having yet been fortunate enough to observe the 

 creatures ovipositing ; and in confinement they will not lay — at 

 least that is my experience. The leaf, in its early growth, seems 

 to have its edge glued down, for if we inspect it with a lens, there 

 will be seen a number of small glutinous points, separated by a 

 small space from each other. I fancy, also, that the insect uses 

 its mandibles to bend it down at first, and then applies the 



