nients. For mass rearing of these late instar larvae for 

 a limited period, 1-gallon ice cream cartons proved to 

 be very satisfactory, fig. 4. A layer of moist sand was 

 placed in the bottom of each carton. A corrugated paper 

 strip was taped around the wall to provide a place for 

 pupation. The food, whole string bean pods, was placed 

 in cylindrical wire baskets made from 8x8 mesh hard- 

 ware cloth; each basket was 2-1/2 inches in diameter 

 and 5-1/2 inches in length. The baskets were then 

 placed on the sand in the cartons and as far as possible 

 from the walls of the cartons. There was ample room for 

 40 to 60 larvae in each carton. The borers were dropped 

 on the food, which they quickly accepted. As the food 

 was consumed, additional baskets provided with food 



were placed in the cartons. The borers moved from bas- 

 ket to basket. The food was never in contact with the 

 wall of a carton; therefore, borers seldom chewed holes 

 in the wall of a carton and escaped. 



For certain experiments that required the keeping 

 of larvae under continuous observation and in individual 

 confinement during their full development, shell vials 

 of standard sizes were preferred as rearing containers. 

 Use of the vials presented numerous problems, such as 

 the condensation of moisture and the inadequacy of cot- 

 ton or cork stoppers and plastic or aluminum caps, as 

 well as suitable storage facilities for large numbers of 

 vials in a manner that would render them individually 

 accessible for easy observation and handling. 



Fig. 5. -Metal clamp rack (28-gauge galvanized sheet iron) designed to hold vials for the rearing of com borei and other 

 larvae in individual confinement. Part A is \ inch wide; it consists of two thicknesses of metal, one folded against the other. 

 Holes are drilled through the two thicknesses; each hole is one-half incli in diameter and is one-half inch distant from the 

 hole or holes nearest it. A strip of 50-mesh screen is inserted between the two thicknesses of metal before part A is bent to 

 form a right angle with part B, which is 2-1/2 inches wide. The surface from which clamp springs (one denoted by C) are 

 fashioned is 1-1/4 inches wide; the metal is sawed at 1-inch intervals and is bent to form the springs, each one of which 

 faces a hole in part A. A strip of wood, D, is riveted to part B to aid in lining up the mouth of each vial with a hole in part A. 

 If lips of the vials are so uneven as to allow escape of young larvae, a 1-inch-wide strip of cellucotton, E, is placed between 

 the lips and part A. A rack of the size illustrated accommodates vials of 17 x 60 mm., 19 x 65 mm., and 20 x 68 mm. 



