( 80 ) 



perhaps this was only the cafe of the real fting, and, upon opening 

 it, I found a fling, notched at the point like a faw, of which I have 

 given a drawing n\Jig. 1 1, E F. 



When I liad attentively viewed this for a conliderable time, I 

 thought it feenied to contain another fting within it; I, therefore, 

 endeavoured to open it, wherein I fucceeded to my wifli, and out 

 of it, at the place marked E F, mfg. 11,1 took two flings, both of 

 the fame make ; a fmall piece of one of them is fliewn at Jig. 1 2, 

 G H : each of thefe was jagged like a faw. 



Hence it appeared, that thofe indentings or teeth, reprefented in 

 fg. 11 , at E F, did not properly belong to that part, but to the ftings 

 enclofed in it ; and, when thofe Ilings were taken out, it appeared 

 neceflary to conclude, that the part which I had taken for the real 

 lling was, in fa6l, only a fecond cafe for the two inner ones : in this 

 fecond fheath, or cafe, as drawn in ^^. 13, is fliewn at I K, the 

 cavity wherein the two flings lay; and fartlier, in Jig. 12, another 

 cavity is to be fcen : all which things, put together, give reafon to 

 conjedlure that, in each of thefe cavities, thei-e may be con- 

 tained fome acrid juice of a poifonous nature. 



From the foregoing obfervations, we may eafily conceive, that 

 thefe minute flies do not merely lay their eggs upon the furface of 

 the leaves, but that, with their flings, they perforate the membranes 

 of the leaf, and depolitc an egg in the cavity ; the maggot iflliing 

 from which, in biting the veffels, caufes the juices of the leaf 

 to iflue forth, which form around it thofe knobs, or excrefcenees, 

 I have defcribed. 



I obferved, among the dead maggots in thefe knobs, two white 

 oblong particles, but fo very minute as to efcapc the view of 

 the naked eye ; thefe I concluded to be eggs, for there was, in 

 no part of them, any refemblance of a maggot, and, the next day, 

 two maggots iflued from them, exatlly of the fame make with thofe 

 M'hich I have faid preyed on the larger maggots. 



After this I took one of thofe voracious maggots from the body 



