Perhaps the most careful methods of rearing grubs in temperate 

 (•limates have been worked out by Mr. J. J. Davis at Lafayette, 

 Indiana (5). His method consists, briefly, in the use of flower pots 

 twelve to sixteen inches in diameter and height, or of cylinders made 

 of metal and wire screening, twenty inches in diameter and two and 

 one-half feet in depth, which are inserted into the ground in 

 such a way as to give natural conditions of moisture and drainage. 

 Necessarily cages such as these, even though each many contain sev- 

 eral grubs, require a rather large amount of space for the rearing 

 of large numbers of grubs; and it must be remembered that only in 

 the results from rearing large numbers of grubs can accurate data 

 be obtained. Under tropical conditions, where there is no winter to 

 contend with, methods requiring much less space have been found 

 quite satisfactory and in most respects preferable. 



Methods of rearing employed by the writer consisted at first in 

 the use of flower pots six inches in diameter and of glass battery jars. 

 The objection to the pots was that they required dumping of the 

 earth in order to view the grubs, which meant disturbance and often 

 injury to the grubs. The objection to the jars was that they allowed 

 for no drainage, and the soil became sour, thus permitting mites 

 and nematodes to breed. Furthermore, in glass jars grubs would 

 seldom remain near enough to the glass to be seen, so there was no 

 advantage gained. 



In all respects the most convenient method was found in the use 

 of two and one-half and three-inch round, seamless tin boxes, one 

 and one-quarter inches high. One or two grubs were kept in each 

 box, the larger grubs being kept in larger boxes. These boxes were 

 conveniently kept in piles and tiers, and were opened and the con- 

 tents examined regularly at intervals of several days to a week or 

 more. Pups were examined almost daily. To prevent rust boxes 

 were first lined with a thin coating of paraffin. Moisture was regu- 

 lated not by adding water to the box, which experience proved w^as 

 dangerous, but by using sifted earth of the right dampness to begin 

 with, and renewing the earth when it became dry or sour. 



Food was supplied by adding a kernel of corn to each box. A 

 new kernel was never added until the old one had been entirely con- 

 sumed, germinating roots and all, as it was found that greater dan- 

 ger came from over feeding than from under feeding. Too much 

 food in a box always led to an accumulation of mites {Tyroffli/phus 

 sp. .'), which would attack and often sicken the grub, finally causing 

 its death unless the mites were carefully brushed ott' and fresh earth 

 supplied. In absence of corn, a small section of cane could be fed; 



61 



