OF THE STATE ENTOMOLOGIST. 39 



by a rule in strips of proper width, allowing' for a tritlc of overlapping on the sides. 

 Its cost per volume is merely nominal. 



First quality single-thick glass for sides must be selected, wholly free from rust, 

 veins, air-bubbles or any blemish. Such glass can be purchased at fifteen cents a pane. 

 The lower glass, after thorough cleaning, especially of its inner surface, witii an alka- 

 line wash, and a final polishing with slightly wetted white printing paper, is to be 

 firmly secured in its place by a proper number of tin points; the upper glass is but 

 temporarily fastened. The binder must be directed to cover the exposed sides of the 

 frame with " combed " paper, bringing it over the border of the permanent lower glass, 

 and beneath the removable upper glass. 



The covers of the volume are of heavy binder's-board (No. 18). neatly lined within 

 with glazed white paper. On one of the insides of the lids may be attached, by its 

 cortiers, a sheet with tlie numbers and names of the species contained in the volume, 

 or these may be placed on the pin bearing^ the insect. If bound in best quality of imi- 

 tation morocco, with cloth covers, lettered and gilded on the back, the cost (for a dozen 

 volumes) need not exceed $1.00 each. If in turkey-morocco, it will be $1.50. 



The lettering and ornamentation of the back will vary with the taste of the indi- 

 vidual. The family designations may be permanently lettered, or they may be pasted 

 on the back, on a slip of paper or gum-label, as are the generic names, thus permitting 

 the change of the contents of a volume at any time, if desired. 



The bits of cork to which the insects are to be pinned are cut in quarter-inch 

 squares from sheet-cork of one-fourth of an inch in thickness. If the trouble be taken 

 to trim off the corners, giving them an octag-onal form, their appearance will be mate- 

 rially improved, and much less care will be required in adjusting them on the glass. 



The cement usually recommended for attaching the cork to the glass is composed 

 of equal parts of white wax and resin. My experience with this has not been favor- 

 able, for after the lapse of a few years, I have invariably been subjected to the serious 

 annoyance of being* compelled to renew the entire contents of the volume, clean the 

 glass and replace the corks with new cement. From some cause, inexplicable to me? 

 a gradual separation takes place of the cork with its cement Irom the glass, first ap- 

 pearing at the angles of the cork, and its progress indicated by an increasing number 

 of iridescent rings which form within, until the centre is reached, when, if not pre- 

 viously detached, the insect falls with the cork, usually to its injury and that of others 

 beneath it. 



A number of years ago, I happened to employ, in attaching a single piece of cork 

 in one of my cases, a cement originally made for other purposes, consisting of six parts 

 of resin, one of wax and one of Venetian red. Several years thereafter, my attention 

 was drawn to this piece, by finding it as firmly united as when at first applied, and at 

 the present time (after the lapse of twelve years) it is without the slightest indication 

 of separation. Acting upon this hint, I have, of late, used this cement in the restora- 

 tion of a number of my cases, and with the most satisfactory results. It is important 

 that the cement, when used, should be heated (by a spirit lamp or gas flame) to as high 

 a degree as it will bear without burning. An amount sufficient to cover tlie bottom of 

 the small, flat metal vessel containing it to the depth of an eighth of an inch will suf- 

 fice, and prevent the cork from taking up more than its requisite quantity. It should 

 be occasionally stirred to prevent the precipitation of its heavier portions. The cork 

 may be conveniently dipped by the aid of a needle inserted in a handle, when, as 

 quickly as possible, it should be transferred to the glass, for the degree of adhesion 

 seems to depend upon the degree of fluidity of the cement. From some experiments 

 made by me, after the corks had been attached as above, in heating the entire glass to 

 such a degree as thoroughly to melt the cement until it spreads outward from beneath 

 the weight of the cork, and then permitted to cool— the glass meanwhile held horizon- 

 tallj', that the corks might not be displaced— the results appear to indicate that the 

 above cement, applied in this manner on glass properly cleaned, will prove a permanejit 

 one. It is scarcely necessary to state that this method is not available where the glass 

 has been bound as above. 



