4 DURHAM DIPTERA. 



COLLECTING AND PRESERVING. 



Flies are not hard to find. The windows will supply repre- 

 sentatives of almost all the families, and if kept open at the 

 bottom and shut at the top they form good fly-traps. A 

 bottle 4-in. high, i^-in. diameter, and f-in. across the mouth, 

 lined inside with blotting paper, and having a small piece of 

 sponge jammed into the bottom, on which a few drops of 

 benzine are dropped when necessary, may be placed over the 

 fly as it crawls up the pane. A few seconds stupify, and a 

 few more result in death. 



Outside there are few situations where flies may not be 

 found. I use a large green net about sixteen inches 

 diameter, mounted on a very strong padded ring, and 

 firmly fastened on a handle about a foot and a half long. 

 At the small end, which is open, is a ring of flat whalebone 

 3-in. diameter, fastened by its lower and inner edge to the 

 outer edge of the net (see Plate VII., 29, 30, 31). To the 

 upper and outer edge of a second flat whalebone ring, just 

 large enough to fit inside the former, is fastened the upper 

 and inner edge of a small white Indian muslin bag about 8-in. 

 long, tapering to 2 -in. diameter at its lower end, where it is 

 closed by a piece of transparent celluloid — part of a watch 

 protector with the rim cut off. A small piece of flat elastic 

 with a hook and eye, a little below the ring, closes the open 

 end of the bag. The whalebone rings allow of the bag being 

 rapidly attached to the net, the larger net-ring being pushed 

 inside the smaller bag-ring. Ten or twelve of these bags may 

 be carried suspended along the sides and top of a box 

 12-in. by 8-in. by 3-in., covered with American cloth, and 

 suspended round the shoulders, in which hundreds of flies, 

 the spoil of successive sweepings, may be carried home alive, 

 and in good condition for leisurely examination. A tin 

 canister, blotting-paper lined, in which the bag is placed with 

 a few drops of ether, soon takes the buzz out of them, when 

 they may be shaken out on a piece of white paper for exam- 

 ination. Those wanted are dropped into the benzine bottle 



