الفهرس 
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Abstract
ABSTRACT
This study was conducted to study some physiological points on certain Lepidopterous insects, cotton leafworm, Spodoptera littoralis and black cutworm, Agrotis ipsilon. Results obtained for rearing cotton leafworm on six different host plants are showed that the highest mean larval consumption was (0.34 & 0.37gm) and (0.35&0.36gm) of lettuce and alfalfa daily in the two successive generations, respectively. Then jaw’s mallow (0.31&0.30gm), cabbage (0.21&0.23gm) while, the lowest mean larval consumption was (0.18&0.19gm) for turnip and (0.17&0.17gm) for castor leaves, respectively. While, A. ipsilon showed that the highest mean larval consumption was (0.48&0.45 gm) and (0.39&0.38gm) of alfalfa and turnip daily in the two successive generations, respectively. Then lettuce (0.33&0.35gm), Jaw’s mallow (0.29&0.30 gm) and cabbage (0.23&0.23gm) while, the lowest mean larval consumption was (0.15& 0.17gm) for castor leaves, respectively. The six different host plants have variable effects on development of larvae of the cotton leafworm, S. littoralis. Results showed that the duration of the larval stage is affected by the different host plants offered. In the first generation the shortest mean duration (13.46&13.57days) were recorded for larvae fed on lettuce and alfalfa, respectively. The same results were recorded in the second generation where the shortest mean duration (13.51& 13.64days) was recorded for the same host plants, respectively. On the other hand, the longest mean period for larval development (17.83, 17.56 and 16.33 days) recorded when larvae were offered turnip, castor leaves and cabbage, respectively in the first generation. Also, the same