8 CHEESE. [1899 



more generally known ; and as it was in my power in the last season 

 to gain some useful information as to presence and prevention of the 

 infestation on a large scale, as observed in the premises of one of our 

 large Curing companies, I give in the pages 10, 12, and 13 the notes 

 which they have been good enough to allow me to use, under promise 

 to withhold any names which might lead to knowledge of locality. 



These maggots are the larvae of a slender shining black two-winged 

 fly (see figure, p. 7), scarcely the fifth of an inch in length. The 

 abdomen longly elliptical, somewhat depressed, and with some amount 

 of fine hair at the sides and tip, Customarily the fore legs are black, 

 with some reddish yellow at the hips and knees ; and the middle, and 

 hinder pairs, reddish yellow with some mixture of black. The wings 

 transparent, overlapping at the edges nearly to the tips when in 

 repose, and with pale veins. 



The eggs are white (possibly sometimes pinky), slender, oblong, 

 slightly curved, and one millimetre — that is, about half a line — in length. 

 These are sometimes deposited singly, sometimes in clusters of from 

 five to fifteen, and as many as thirty may be deposited by a single fly. 

 The duration of egg condition may only be for thirty-six hours or less 

 in summer, but appears to vary with temperature. ''' 



The larvaB, or maggots, are whitish in colour, and legless, smooth, 

 and shining, cylindrical in shape, taperiug to the head, and truncate 

 or somewhat rounded at the tail extremity, which is furnished above 

 with two horny "stigmata," or spiracles, the trachete, or breathing- 

 tubes, connected with these breathing-pores being clearly visible 

 through the thin skin ; beneath are a pair of fleshy processes, and 

 there is a smaller process at each side. (See figures 4 and 5, magnified, 

 and greatly magnified, drawn from life, at p. 7.) 



When full grown the maggot measures about a third of an inch in 

 length. The head extremity is furnished within with a pair of hooks, 

 which serve for collecting its food, or at pleasure (when it has com- 

 pleted its growth, which may be in about seven or eight days) may 

 help to drag it to the spot selected for turning to chrysalis state. 

 These hooks are also of service in the very noticeable habit of the 

 maggot of putting head to tail and taking long skips, or leaps, which 

 is thus described in detail f : — " When about to leap the larva brings 

 the under side of the abdomen toward the head while lying on its side, 

 and reaching forward with its head, and at the same time extending 



* For detailed inforiuation on this attack, see " The Cheese or Meat Skipper," 

 by Mary E. Murtfeldt, 'Insect Life' of Dept. of Agriculture, U.S.A., vol. vi. 

 pp. 170-175; and also "Cheese Skipper or Ham Skipper," by L. 0. Howard, in 

 ' Principal Household Insects of the United States,' Bulletin No. 4, New Series, 

 Dept. of Agriculture, U.S.A., pp. 102-104. 



+ See observations by Prof. Putnam in Dr. Packard's ' Guide to Insect Life.' 



