ENTOMOLOGICAL SOCIETY OF ONTARIO. 101 



have lost its skipping power, and was constantly thrusting its head or its posterior 

 extremity into the deserted puparia that were scattered at the bottom of the jar. Whether 

 it was aljle to complete its transibrmations I can not now say.) 



Both transformations, although involving such radical, formal and functional changes,, 

 take place within a period of ten days, as nearly as I have been able to ascertain. 



The perfect insect is a shining black fly with bronzy tints on the thorax and slight 

 iridescence of the wings. The latter overlap nearly to the tips when the insect is at rest. 

 The legs are dull black, shaded at the joints to dull yello a^ or fuscous. In size it is about 

 one-half that of the common house ily. There is no good figure of this insect in any 

 American publication, that in Packard's Guide being in outline merely and not available 

 for recognition except by the skilled entomologist. The fly is not active at night, bat is 

 able to perform its life work in the obscurity of partially darkened closets and store- 

 rooms. To make these absolutely dark would, in my judgment, effectually exclude it. 



I have not been able to make it oviposit on fresh meat of any kind, nor does it seem 

 able to breed upon that which is .simply salted, but not smoked, not even when such meat 

 is folded in wrapping papers. It will sip a little at sweets, but is not greatly attracted to 

 them, while the odor of smoke 1 meat speedily summons it. The average duration of life, 

 in the perfect state, in summer, does not exceed a week, according to observations made 

 upon it in the rearing jar, which rnny not, however, exactly indicate it. The entire life 

 cycle would seem to be included within three weeks, but there is no definite succession of 

 broods, and the insect may be found in all stages from May until October or November. 

 When exposed to severe and protracted cold, larvae, pup;c and flies are killed. The flies 

 speedily succumb to the fumes of burning sulphur or pyrethrum powder, and the latter, if 

 dusted upon them, produces the same stupefying effect that it does upon other Dipfcera. 

 The firm in whose behalf these investigations were undertaken informs me that in order 

 to exclude the fly they screened all windows and doors with a 24 to the inch wire mesh. 

 They also, early in the spring, thoroughly whitewashed and fumigated smoke-liouses and 

 storerooms, using an admixture of carbolic acid in the whitewash, thus effectually sealing 

 up or killing all hibernating individuals that might be lurking in these places. I have not 

 been able to recommend any repellant chemical that could be safely incorporated with 



the wash used on the outside of the wrappers. Mr. D also informs me that sulphur 



fumes in the storerooms give a streaked and unattractive look to the wash, and th3 use of 

 this repellant is therefore impracticable. 



Smoked beef also suffers to some extent from the attacks of this insect, but, as Mr. 



D says, "not nearly so badly as pork. If a beef ham were hanging beside that of a 



hog, the former would most likely be O. K., while the latter would be stung." 



In my correspondence with cheese manufacturers I learn that the loss of their pro- 

 ducts is now far less than it formerly was 



One of our leading cream-cheese makers writes : 



We are always somfiwhat troubled with the cheese flies in summer. To keep them out of our stor^ 

 rooms we cover the windowM with light domestic, as they will go through the ordinary wire screen, but a® 

 there will always be more or less of them in the rooms, we have the brown fly uaner in water always on 

 hand, which keeps them pretty well in check. They are worst during the hor; seas'jn. We do not use any 

 chemicals, as they would be likely to injure the (juality of the cheese. The flies deposit their eggs on the 

 outside of the chees(;, and in tliirty to thirty-six hours they begin to squirm and work their way intide, so 

 we usually go through the rooms twice a day and look for eggs. They are easily f')und on the smooth sur- 

 face, but if the bandage is wrinkled or cracked we sonietinves miss them. We have not had over $5 worth 

 destroyed in two years, and are turning out 800 cheeses par day. 



Another large manufacturer informs me that he 



depends mainly upon fine screens to keep out the fly, and also darkens his storerooms ; has each chees^ 

 rubbed hard each morning ; iises no chemicals, but a cheese grease that contains some rosin, which gives * 

 hard coating. Loss not more than 1 per cent., some seasons not over one-fourth of 1 per cent. 



These reports are encouraging as showing with what comparative ease the insect may 

 be kept in check when once its habits are thoroughly understood. It is hoped that these 

 few notes, not in all particulars conclusive, may prove of some assistance in popu- 

 larizing that knowledge. 



Mr. Aldrich spoke of an English custom of placing cheese under the tap of a beer 

 keg, so that the drip would encourage the development of the insect. He had been 

 informed that the maggots improved the quality of the cheese. 



