THE COLLECTION AND PRESERVATION OF DIPTERA 155 



desired to remove or whatever space it is desired to fill. 

 The risk of damaging specimens with the coat-sleeve, a 

 calamity of frequent occurrence under any other arrange- 

 ment, is thus reduced to a minimum. With regard to the 

 labelling of the columns it is sufficient to state that the 

 name of the genus should come at the head of the column 

 or portion of column containing its various species, while the 

 species label should be placed below the series of specimens 

 of that species. The generic name should be in capital 

 letters an-d the label should not be repeated, while the 

 specific name should be in small ("lower case") letters and 

 may, if preferred, be preceded by the initial of the genus. 

 Finally, when arranged, the cartons or store-boxes may 

 be stored on edge on ordinary book-shelves, with a label 

 pasted on the front edge to indicate the contents. Extreme 

 care must of course be observed in handling the boxes, and 

 if freedom from jolting cannot be guaranteed the boxes, and 

 more especially the one-sided cartons, should be kept 

 in a horizontal position, i.e., in piles upon each other, the 

 cartons in every case with the lid uppermost. 



In conclusion, a few hints may be given regarding the 

 actual examination of specimens. A good platyscopic lens 

 magnifying 20 diameters is the most generally useful, 

 and will suffice for the identification of nearly all species. 

 For rough classifying a lens of lower power, say 10 diameters, 

 will be found handy, but for the working out of the tiniest 

 species {f.g., Phoridas, Chironomidae, Cecidomyiidae) the ideal 

 instrument is a stereoscopic microscope. It is wonderful, 

 however, what can be done with only a simple hand-lens 

 of the power indicated, and the occasions upon which it is 

 necessary to call in the aid of a compound microscope are 

 seldom indeed. Advanced students who work out details 

 of anatomy, internal or external (chaetotaxy, genitalia, etc.), 

 require, of course, the best microscope they can procure, 

 while those who desire to draw for the purpose of illustrating 

 their memoirs require in addition a camera lucida and 

 various other accessories. To enter into details on these 

 points would, however, carry us beyond the scope of the 

 present paper, which is primarily intended for beginners. 



