334 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 15 



perpetuation of the species. It is a recognized fact, as has been pointed 

 out by Hewitt^, Brues^, and others that in most cases the female insect 

 selects the larval food by depositing its eggs on substances best suited 

 for the nourishment of the larvae and that this instinctive behavior or 

 response to chemical stimuli has untold possibilities in the solution of 

 many entomological problems. Brues attributes the selection of food 

 plants to one or several factors, namely, (1) the odor and taste of the 

 plant, (2) some attribute of the plant, perhaps an odor, but far less pro- 

 nounced to our senses, (3) a similarity of the immediate environment or 

 general form of the plant, and (4) apparent chance associations that 

 have become fixed whereby diverse plants are utilized by oligophagus 

 species. 



In the study of the com earworm (Chloridea obsoleta Fabr.) which has 

 been in progress at this Station for several years, considerable attention 

 has been given to oviposition, since the plants and parts of plants select- 

 ed for egg deposition determine largely the feeding habits of the larvae. 

 The com earworm presents many difficulties in a study of its field activi- 

 ties because of its cosmopolitan distribution and wide range of food 

 plants. It is generally conceded, however, that throughout its habitat 

 it manifests a decided preference for the corn plant wherever present. 



A review of the literature indicates that comparatively little study 

 has been made of oviposition, and many workers leave the impression 

 that the eggs are deposited indiscriminately on the plant. Quaintance 

 and BruesS however, state that in the case of com, the silks are usually 

 chosen first if these are present on the plants. Egg counts which they 

 made on silking plants indicate that approximately 40 percent of the 

 eggs are deposited on the silks. These writers followed the oviposition 

 on cotton and found a more promiscuous distribution of the eggs. A 

 Total of 1141 eggs were found on cotton, 28.5 percent of which were 

 deposited on the squares, and they state that it is quite possible that the 

 large number of eggs laid on the squares is accidental and due to the 

 attraction offered by them on account of the nectaries on which the 

 moths feed. At any rate, the moths appear to oviposit indiscriminately 

 wherever they happen to alight on the plant. 



^Hewitt, C. G., Insect Behavior as a factor in Applied Entomology. In Journ. 

 Econ. Ent. 10:81-91, 1917. 



^Brues, C T., The Selection of Food-Plants by Insects with Special Reference to 

 Lepidopterous Larvae. In Amer. Nat. 54:313-332, 1920. 



^Quaintance, A. L., and Brues, C. T., The Cotton Boll-worm. U. S. Dept. Agri., 

 Bu. Ent. Bui. 50, 155 p., 1905. 



