In Fig. 133 is a cross section through one side of the box, showing how it should be made and giving measurements. In the drawing the glass is fitted into a groove in the inner side of the cover. This glass might be puttied in like a window pane if it is found difficult to make the groove. The corners of the box may be mitred and dove-tailed, or mitred and nailed; the latter is more easily done. Any carpenter or cabinet maker can make this box. Great care must be taken to use only thoroughly seasoned wood in its construction; otherwise the bottom will be sure to warp and shrink and leave cracks through which the museum pests will enter. The cost of such a box will vary from $0.75 to $1. Basswood should be used for its construction; pine is not at all suitable on account of the resin in it. Screw eyes may be put into these boxes and they may be hung on the walls of the schoolroom like pictures. MUSEUM PESTS. These are small beetles which find their way through the narrowest crevice into the insect boxes and lay their eggs on the pinned insects. The larvæ when they hatch work within the specimens at first but after a time destroy the bodies entirely. The presence of these little rascals may be detected by dust on the bottom of the box just below the infested insect. As soon as this dust is observed, pour into one corner of the box a tablespoonful of carbon bisulfide, or benzine, and close the box quickly. The teacher or parent should put the substances into the boxes, as the first is a poison and both are very inflammable. As a method of preventing the beetles from attacking the collection it is well to fasten a "moth ball" into one corner of the box. These may be obtained at a drug store. SPREADING-BOARD. FIG. 134. Butterflies and moths look much better in a collection when their wings are extended at right angles to the length of the body. To arrange them thus we have to use what is termed a spreading-board. [Illustration: _Fig. 134. A spreading-board._] _Materials needed for a medium sized spreading-board._ 1. Two strips of pine or other soft wood 18 inches long, 1-1/2 inches wide and 1/2 inch thick. 2. One strip of wood 18 inches long, 3-1/4 inches wide and 1/2 inch thick. 3. Two cleats 3-1/4 inches wide, 3/4 inch high and 1/2 inch thick; and two cleats 1 inch wide and as high and thick as the others. 4. A strip of cork or linoleum 17 inches long and a little less than an inch wide.