476 Phylum Arthropoda 



CARE AND HATCHING OF THE EGGS 



The eggs are removed from the soil by sifting it at intervals. They 

 are considerably smaller when freshly laid than later when they increase 

 considerably in size by absorption of water. Their white color, however, 

 makes it relatively easy to detect them and pick them out of the darker 

 soil irrespective of whether they do or do not pass through the sieve. 

 Eggs are transferred to the hatching boxes by means of a slightly 

 moistened camel's hair brush. The hatching boxes are each about three- 

 fourths filled with finely sifted soil, previously sterilized and moistened 

 by kneading with tap water. One-ounce or two-ounce metal salve boxes 

 are satisfactory for this purpose. The soil is packed down in the box 

 until its surface is firm enough to enable crater-like pits to be made in it 

 which retain their shape. One egg is placed in each of these pits. To 

 prevent the larvae, as they hatch, from crawling out of their pits and 

 straying into others, the pits are made about one-fourth inch deep with 

 vertical sides. The soil may be sterilized by heating it in an oven for 

 several hours at a temperature of ioo° to 150° C. (212 to 301 F.), 

 or by fumigation with carbon bisulphide or chloroform for a period of 

 about 24 hours. 



The boxes containing the eggs should be placed in an incubator at the 

 desired temperature. Ludwig (1928) found that at 30 C. (86° F.) 

 development of the eggs of the Japanese beetle occurred most rapidly. 

 The eggs of this species are not likely to hatch at constant temperatures 

 above 33° C. or below 15 C. (59 F.). Furthermore, in 1930 he 

 demonstrated that long exposures to a temperature as low as io° C. 

 (50 F.) will delay the hatching of the larvae when they are subse- 

 quently placed at higher temperatures. 



The eggs should be examined daily to make certain that moisture 

 conditions are favorable and to note the progress of development. When 

 needed, water can be added from a pipette, but care must be taken to 

 avoid an excess, which might prove detrimental since it favors the growth 

 of parasitic molds that kill the eggs. Hatching may be anticipated by 

 noting the appearance of the brown jaws of the developing larvae, which 

 can be seen through the egg membrane. 



CARE AND FEEDING OF THE LARVAE 



For the general rearing of scarabaeid larvae, the one-ounce metal salve 

 boxes recommended by Davis (1915, plate 5, figs. 10-12) are satis- 

 factory. On account of the pugnacious habits of the larvae, it is unsafe 

 to place more than one individual in a box. 



The medium used in the rearing boxes should be sifted and sterilized. 

 It may be quite varied in nature and composition, the main considera- 



