Helodidae 457 



Lane, 1924; Stone, 1935) but the writer has obtained higher survivals of 

 young A. mancus larvae by using 6-inch moist chambers than by the 

 use of drain tiles or clay pots. Young larvae require sprouting seeds or 

 living plant roots as food. The food requirements of young wireworm 

 larvae needs further investigation, for our present knowledge is contra- 

 dictory and incomplete. 



Cast skins, particularly of the first instars, are difficult to find in the 

 soil because of their small size. Stone has suggested a method whereby 

 the exuviae are easily located. Cells 1 inch in diameter and 3 inches 

 deep were made in a plaster of paris block. A newly hatched larva was 

 placed in each cell containing starchy material from corn grains and the 

 block was then placed in the dark. Moisture was provided by adding 

 water to the block from time to time. After the 3rd or 4th instar the 

 larvae were transferred to salve boxes. An abundance of food was pro- 

 vided at intervals. 



Pupae are difficult to handle and high mortalities generally occur. 

 Observations on this stage are successfully made by transferring larvae 

 in the prepupal stage to individual cages. They are placed on the bot- 

 tom of small vials and the vials then filled with moist soil. Larvae 

 form pupal cells near the glass sides of the vials and the progress of 

 pupation may be easily followed. When salve boxes are used the pre- 

 pupae are placed in depressions made in the moist soil by the tip of the 

 forefinger or thumb (Stone, 1935). 



Bibliography 



Bryson, H. R. 1929. A method for rearing wireworms. J. Kans. Ent. Soc. 2:15. 

 Lane, M. C. 1924. Simple methods of rearing wireworms (Elateridae) . J. Econ. 



Ent. 17:578. 

 McColloch, J. W. 191 7. A method for the study of underground insects. Ibid. 



10:183-188. 

 Peterson, Alvah. 1934. A manual of entomological equipment and methods. 



Parti. Pis. 37-42; 72-73. 

 Stone, M. W. 1935. Technique for life-history studies of wireworms. J. Econ. 



Ent. 28:817-824. 



Family helodidae 



SCIRTES TIBIALIS* 



ALTHOUGH aquatic, the larva is not an open water swimmer. It 

 l. has a distribution restricted to that of the duckweed, Lemna minor, 

 its one food plant. The larvae are usually found resting on the lower 

 surfaces of the Lemna leaves. 



♦Abstracted from an article in Ann. Ent. Soc. Amer. 11:393, 1918, by Walter C. 

 Kraatz, University of Wisconsin. 



