and a sucking insect at the sanie time by using the 

 split bean technique. 



Nutritional and other physiological studies might 

 also profit from use of the split bean technique if the 

 bean plant is grown in a medium containing nutrients 

 labeled with radioactive isotopes. 



For studies with systemic compounds, the floating 

 leaf technique might be employed with known amounts 

 of the compounds added to the water. Not only the mor- 

 tality of the larvae but also their reactions could be ob- 

 served. The extraction thimble technique could be adap- 

 ted for experiments with granulated compounds by de- 

 positing the granules between the rolled leaves. 



Some of the rearing and research techniques de- 

 scribed above have with certain modifications been 

 used in work involving lepidopterous larvae other than 

 those of the corn borer. The experience gained while 

 working with them probably deserves a brief mention. 



Larvae of the corn eaTwontiJieliolhis zei? (Hoddie), 

 were sometimes reared in great numbers in the labora- 

 tory. Because of their cannibalistic habits, the larvae 

 had to be kept in individual confinement. Vials of 19 x 

 65 mm. size were found to be suitable for rearing the 

 larvae. The vials were stored either in metal clamp 

 racks, fig. 5, or in wooden racks. It was advisable, at 

 the time the larvae were in the first instar, to seal the 

 orifice of each vial in the wooden racks with a piece 



of tinfoil, 2x2 inches in size, in order to prevent es- 

 cape of the larvae. Subsequently, aluminum caps, de- 

 signed for 18 mm. bacterial culture tubes, were used 

 instead of conventional cotton plugs. The formation of 

 excessive amounts of condensed moisture, which could 

 be very bothersome, was prevented by providing each 

 aluminum cap with a seven-sixteenths-inch hole. Then 

 the hole was plugged with a piece of dental cotton 

 wick. For food, pieces of green beans were used ex- 

 clusively and with very good results. 



I.arvae of the variegated cutworm, Peridroma mar- 

 garitosa (Haw.), were reared in similar manner. The 

 larvae were, at times, reluctant to accept whole bean 

 pods. However, if the beans were split, the larvae fed 

 on them and developed normally. 



Because of the gregarious habits of larvae of the 

 amiyworm, Pseudaletia unipuncta{i^aw), the mass reai^ 

 ing of this insect usually did not involve many difficul- 

 ties. When arniyworms had to be reared individually, the 

 maintaining of proper humidity was of primary signifi- 

 cance. This was achieved very simply by pouring a 

 layer of 4 per cent agar, 10 mm. deep, into the bottom 

 of a 14 X 75 mm. vial, a size which was found to be the 

 most satisfactory for this purpose. The surface of the 

 agar had to be dried for about 12 hours to prevent the 

 larvae from sticking to the surface. The young larvae 

 were fed on oat leaves at first and later on com leaves. 



LITERATURE CITED 



Beck, S. D., J. H. Lilly, and J. F. Stauffer 



1949. Nutrition of the European corn borer, Pyrausta nubilalis (Hbn.). I. Development of a satisfactory purified diet for 

 larval growth. Ent. Soc. Ann. 42:483-96. 

 Bottger, G. T. 



1940. Preliminary studies of the nutritive requirements of the European com borer. Jour. Ag. Res. 60:249-57. 

 Bottger, G. T. 



1942. Development of synthetic food media for use in nutrition studies of the European com borer. Jour. Ap. Res. 65: 193- 

 500. 

 Mathes, Ralph 



1936. Three factors affecting laboratory rearing of European com borer larvae. Jour. Econ. Ent. 29:691-97. 





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