Eight-hundred-three moths were irradiated with 10-second exposures of radiation in bands 100 Angstroms wide at 200 A. intervals. The main range covered was 3150 to 4550 A. Four controlled temperatures between 60 and 80 F. were used. Observations of individual moth responses were combined to determine the most stimulating band, the effect of temperature, and effects of species, sex, time of testing, and moth origin. Within the wavelength range, a band centered at 3150 A. had the most reactions and one at 4350 A. the least. The total group of moths tested over these bands had a plot of reactions versus wavelength with no reversals of slope between maximum and minimum. No definite effects of temperature, sex, time of testing, or moth origin were found. The tomato hornworm moth was definitely the less active species and showed a greater difference between bands of maximum and minimum reactions. An additional test found no effect due to the relative intensity of radiation on different bands, which was not equalized in the main tests. Only teat groups which allowed for several hundred possible moth reactions at each treatment showed consistent trends. / Master of Science