548 Saw-flies, Gall-flies, Ichneumons, 



and its auxiliary, Formica schaujussi (Proc. Phil. Acad. Sci., 1880, p. 376 

 et seq.). 



The observation and study of ants' ways must be partly done in the 

 field, but, thanks to the obliging manner in which most species will readily 

 live in artificial nests, prepared for them indoors, much intensely interesting 

 work in the study of ants can be done on one's own reading-table. Several 

 types of artificial formicaries (ants' nests) have been devised, one by Lub- 

 bock, another by Forel, another by Janet, another by White, etc., any one 

 of which seems to give good results. Professor Comstock gives the follow- 

 ing directions for making a Lubbock nest: "The principal materials needed 

 for the construction of a riest of this kind are two panes of window-glass ten 

 inches square, a sheet of tin n inches square, and a piece of plank i^ inches 

 thick, 20 inches long, and at least 16 inches wide. 



"To make the nest, proceed as follows: Cut a triangular piece about 

 i inch long on its two short sides from one corner of one of the panes of glass. 

 From the sheet of tin make a tray f of an inch in depth. This tray will be 

 a little wider than the panes of glass and will contain them easily. On the 

 upper side of the plank a short distance from the edge cut a deep furrow. 

 This plank is to form the base of the nest, and the furrow is to serve as a 

 moat, which is to be kept filled with water in order to prevent the escape 

 of the ants. It is necessary to paint the base with several coats of paint to 

 protect it from water and thus prevent its warping. 



"To prepare the nest for use, place the tin tray on the base, put in the 

 tray the square pane of glass, lay on the edges of the glass four strips of wood 

 about inch wide and a little thicker than the height of the ants which are 

 to be kept in the nest, cover the glass with a layer of fine earth of the same 

 thickness as the strips of wood, place upon this layer of earth and the strips 

 of wood the pane of glass from which one corner has been cut, and cover the 

 whole with a cover of the same size and shape as the upper pane of glass. 

 In the nest figured the cover is made of blackened tin, and one-half of it is 

 covered by a board. This gives a variation in temperature in different parts 

 of the nest when it stands in the sunlight. 



"The ants when established in the nest are to mine in the earth between 

 the two plates of glass. The removal of one corner from the upper pane 

 provides an opening to the nest. The thickness of the strips of wood between 

 the edges of the two panes of glass determines the depth of the layer of earth 

 in which the ants live. This should not be much thicker than the ants are 

 high; for, if it is, the ants will be able to conceal themselves so that they can- 

 not be observed. 



" The nest being prepared, the next step is to transfer a colony of ants to it. 

 The things needed with which to do this are a two-quart glass fruit-can, or 

 some similar vessel that can be closed tightly, a clean vial, and a garden 



