568 
Journal of Agricultural Research 
Vol. XXXI, No. 6 
Type C.—Square, base inclosing 1 square yard. Height, 18 inches- 
Frame of 1 by 2 inch cypress, covered with 18-mesh pearl screen wire. 
Top is made to open upward to facilitate counting of flies. The entire 
cage is lined with cheesecloth. Four single sheets of tanglefoot fly 
paper are fastened to the lower side of the top (fig. 1, C). 
Type D. —This is a light-proof box of 0.5-inch pine, with base 
inclosing 1 square yard. In later experiments this type was made of 
a wood frame covered with tar paper. Two 29-millimeter glass vials 
were inserted through holes bored in the south side of the box (fig. 
1,D). 
Fig. 1 .—A, emergence cage for the Hessian fly, type A, having cone-shaped frame of sheet tin, covered 
with screen wire; B, emergence cage, type B, having square frame of cypress, covered with screen 
wire; C f emergence cage, type C, having square frame of cypress, covered with screen wire and lined 
with cheesecloth; D, dark emergence cage having frame of wood, made light-proof with tar-paper 
covering 
Type E.—-May be described as A-shaped, with square base inclos¬ 
ing 1 square yard. The two sloping sides are 1 yard square each and 
the ends A-shaped. Frame of 1 by 2 inch cypress, covered with 
18-mesh pearl screen wire. Door, made by hinging one of the sloping 
sides at the top, is painted with thin tanglefoot, and the cage set so 
that this door faces south (fig. 2 , A). 
Type F.—This may be described as A-shaped with base square, 
inclosing 1 square yard; the two sloping sides 1 yard square each, and 
the ends A-shaped. Frame of 1 by 2 inch cypress, covered with 
18-mesh pearl screen wire, with the exception of the door, which is 
made by having one of the sloping sides hinged at the top. This door 
is covered with 12-mesh pearl screen wire and painted with thin tangle¬ 
foot. The cage is set so that this door Dues south (fig. 2, D). 
