Tiphiidae and Scoliidae 503 



rearings will have to be conducted to supply the information needed for 

 their recognition. If larvae are used that are not true hosts, the oviposi- 

 tion of the parasite will usually be slow and intermittent, or there will be 

 no oviposition. Eggs that remain attached in such cases may hatch and 

 a few larvae may reach maturity, but ordinarily the subsequent develop- 

 ment of the parasite is not completed. In the tiphiids the position of 

 the egg on the host is constant for each species but varies with the 

 different species. The number of eggs per female usually ranges between 

 50 and 100. 



A propagation container that has proved satisfactory consists of a 

 tin salve box, of 6-ounce capacity, that is 2% inches in diameter and 

 2 inches in depth. The box should be fitted with a wire screen separator 

 which divides the box into four or more equal compartments, to prevent 

 host mortality through injury and cannibalism. One host larva is placed 

 in each compartment. 



The separators are made of wire screen sufficiently coarse to allow 

 the passage of the parasite from one compartment to another but fine 

 enough to prevent such movement by the host. The size of the mesh 

 used should therefore be gauged according to the size of the parasite and 

 its host. Separators may be constructed by placing together two or 

 more strips of wire screen of the desired mesh, the length of these being 

 about the diameter of the propagation container and the width slightly 

 less than the depth of the container. These strips are fastened to- 

 gether in the center by means of a brass paper fastener of the split-pin 

 type and are then bent apart so that when they are placed inside the box 

 it is divided into equal compartments. From 4 to 6 compartments have 

 been used successfully. 



When the grubs are placed in the compartments of the propagation 

 tins they are covered with soil that has been sifted through a 3- or 4-mesh 

 screen. This soil should be sufficiently moist so that when a handful 

 is pressed together it will form a ball that is easily friable. The container 

 should be filled level and the soil then pressed down firmly so as to be 

 about one-half inch below the edge of the tin. The pressure of the soil 

 will not injure the host grub, which is at the bottom of the tin. Com- 

 pression of the soil is necessary so that the grub may form in it an earthen 

 cell that will not collapse. A convenient tool for compressing soil in 

 the tins consists of a circular wooden disk with a handle attached at the 

 center, the disk being slightly less in diameter than the circular opening 

 of the propagation tin. 



When the box has been prepared as just described, food for the para- 

 site is provided. This may consist of a 10 per cent solution of honey 

 and water, or candy. A convenient candy is made by mixing honey and 

 pulverized sugar. To an ounce of honey add enough sugar to make a 



