The Scottish Naturalist. 257 



present, but two specimens were obtained higher up on the 

 branches where their prey was still rife and active. Afterwards 

 on the 6th of May, I found numbers of them on the Scotch 

 pine, particularly in the axils of the leaves, concealed by the 

 white cottony covering of Adelges corticalis, which adhered so 

 closly to them, that they were only to be detected by the pro- 

 jection of the hinder apex. 



The maggot is narrowish, white, shining, nearly spindle- 

 shaped, fore-end much tapered ; hinder somewhat again con- 

 tracted and slightly rounded; segments well defined, each 

 annulated with ridged rings, very thickly be-set with short 

 hirsuties ; whitest anteriorly, yellower towards the middle, 

 with black or brownish specks below and above from the 

 nature of the food ; mouth provided with two black hooks ; the 

 tracheae wind very much; the fore-stigmata* imperceptible, 

 probably opening close behind the head ; the hinder stigmata 

 two dusky slightly projecting, not widely placed processes ; 

 not far below them, making with them an isosceles triangle, the 

 apex projects somewhat ; at its tip is the anus, which appears 

 like a shining brown plate or valve, with a brown irregular 

 edge. Length 1-1^ line. It uses its oral hooks to facilitate 

 progression by dragging itself onwards ; its excrement is black 

 and adhesive like pitch, and previously to entering into the 

 pupa state it discharges a quantity, which glues it to the object 

 on which it is lying, to which it is closely applied, and on which 

 the pupa-case is partially moulded. Both maggots and puparia 

 are dusted over with the flakes of the cottony exudation from 

 the Adelges. 



I obtained the pupa-case at the same time as I did the 

 maggot. It is somewhat oblong, the segments scarcely 

 indicated, the pubescence still visible, light brown, sometimes 

 darker, the fore tip and the under side paler, or chestnut ; only 

 slightly shining ; the underside flattened ; contracted at the 

 fore-tip, where the upper surface is rather depressed ; the cast- 

 off oral hooks visible under the skin to which they adhere ; 

 hinder apex emarginate ; 1 line long. A portion of the case 

 often comes away on attempting to detach it from its support ; 

 this is at the fore end, from which a portion is detached to ad- 

 mit of the fly obtaining its freedom. 



The fly appeared on the 20th of May, and for some time 



