On the hourly activity of certain Lepidopterous cotton pests as indicated by light-trap catches. The curves illustrating the hourly catches in an ultra violet trap of six species of cotton insect pests indicate the following : The cotton leaf-worm moths Spodoptera littoralis are active all the night, with two distinct peaks, the first about 3 hours after sunset and the second about 3 hours before sunrise. The lesser cotton leaf worm moths Sp . exigua are mainly active during the second half of the night . The pink boll worm Pectinophora gossypiella, thejspiny boll worm . Earias insulana and the American boll worm Heliothis zea are, as a rule, more active during the first half of the night . Their activity diminishes gradually after midnight . Within the three species, the curve representing H . zea maintains an intermediate position between those of P . gossypiella and E. insulana . The pattern of night activity of the cutworm, Agrotis ypsilon, resembles those of the three bollworms.
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