66 The Scottish Naturalist. 



state. It may be easily understood, how, as is generally the 

 case with insects, the male thus anticipate the females ; being 

 of less bulk, they will be more quickly fed, and will on this 

 account precede the other sex in arriving at a state of quiescence, 

 whereas the females, being more robust, will require a longer 

 period for being satiated. 



The maggot is yellowish-white, sometimes slightly dusky in 

 the middle anteriorly, owing to the food shining through, and 

 occasionally reddish-brown posteriorly; elongate fusiform, 

 rather attenuated towards the fore end; the posterior apical 

 segment less broad than the preceding, truncate ; the segments 

 very distinctly separated, slightly ventricose ; with a longitudi- 

 nal series of shallow depressions along each side ; two fibre- 

 like white tracheae distinctly visible, somewhat converging pos- 

 teriorly, where they terminate in two closely approximated 

 tubercles, each capped by a chestnut plate (stigmata) situated 

 a little below the tumid superior margin of the apical trunca- 

 tion ; widening out anteriorly, and then again drawing near to 

 each other behind the head, and descending to the sides, where 

 their opening is indicated by two ovate chestnut scales, one on 

 each side, near the base of the second segment ; mouth pro- 

 vided with two black corneous hooks, contractile within the 

 next segment ; truncate end descending rather abruptly, tri- 

 angulate-conic, a transverse wrinkle beneath the stigmata, fol- 

 lowed by a ridge, which offers from four to six minute elevations, 

 beneath this it contracts into a double tubercle, the substitute 

 for a proleg, behind which there are two slight tubercula on 

 each side of a slit ; the middle of the ventral rings closely 

 striolate across. Length from 2 to 3 lines. 



The pupa-case is formed of the indurated skin of the maggot, and 

 may be considered as a self-constructed cast of the body, several 

 of whose distinguishing features it still exhibits. It is of a brown 

 colour, and is oblong oval, the posterior end being rather nar- 

 rowest, crossed with rather close fine ridges, somewhat roughish or 

 granulated on the inferior surface ; a row of slight hollows along 

 the sides, below and above ; the anterior end with a lamella at 

 each angle, with the interval between them rugose ; the first 

 three segments keeled at the sides, with a depression along 

 their superior edges; the posterior apical segment smallest, 

 roundish at the apex and rugose, bearing a pair of sub-conical 



