14 PROTECTION OF PLANTS, 1918-19 



water. The top of the globe or chimney is covered with cheesecloth muslin tied 

 on securely. Professors Comstock and Slingerland used a modified form of this 

 type of cage in their studies of wireworms (Figs. 5 and 6). A glass cylinder took 

 the place of the lantern chimney, buf it was cemented in place with plaster of 

 paris to prevent the wireworms from escaping. The flower pot was plugged at 

 the bottom and placed inside a larger one, the intervening space being filled with 

 sphagnum which was kept wet. Sufficient water "passed through the porous sides 

 of the pot to keep the soil in good condition" (Bull. 33, Cornell. 1891). 



In recent studies of white-grubs in Indiana, Mr. J.J. Davis has devised some 

 new forms of root-cages for field work, which he buried in the soil (Figs. 8 and 9). 

 Flower-pot cages of various sizes (12, 15, 16 inches in diameter and depth) as 

 well as cylinder-shaped cans of 18-inch galvanized wire cloth with wire 

 covers. Mr. Davis says he found the flower-pot cages the most satisfactory, 

 being "easily handled, cheap and well suited for underground insects." He also 

 used as a check cage a large rectangular cage 8 ft. long, 5 ft. wide, and 5 ft. high, 

 buried for 2§ ft. in the soil (Fig. 10). This cage is constructed of metal and 

 wooden frames and covered with 18 mesh pearl wire cloth. It was found useful 

 also in studying the seasonal life history of the army worm. 



Care must be taken, however, to w^ater the soil in the cages and to make 

 conditions like those in ordinary soil. "During the winter the covers are removed 

 and the pots covered with straw and this with strawy manure to a depth of one 

 foot, which will gradually pack down to a comparatively thin layer." 



For getting eggs and records of individual pairs of white-grubs Davis fills 

 12-inch three-quarter or standard size pots with finely sifted soil. If the soil is 

 kept properly watered the ball-like masses of earth containing the eggs can be 

 obtained by sifting and placed in shallow tin egg-cages in cavities in the soil 

 (Fig. 11). 



Davis found one-ounce tin salve-boxes most satisfactory for studying the 

 habits, growth, and moults of the larvae (Figs. 12, 13). The boxes are filled with 

 soil and moistened to the proper degree and a grain or two of wheat or corn added. 

 The boxes may be placed in tin trays in a cabinet and thus easih- examined. In 

 preparing the boxes for over-wintering all grain and vegetation are removed, the 

 soil, carefully watered, and the tin trap's are buried in a compost heap to a depth 

 of from one to two feet. 



More Elaborate Cages and Insectaries — Professor Comstock of Cornell 

 was one of the first to build an insectary for the study of insects. It contained as 

 essential features a conservatory divided into a hot house and a cold house, a 

 cold room for hibernating insects in the basement, a workshop, a photographic 

 room, a store-room and an ofifice. This building was used for about twenty-five 



