The present title describes the entire work on this topic in five different sections to accomplish specific objectives. Section (1) describes determination of effect of low temperature treatment on longevity and morphological characteristics of P. ricini larvae. Section (2) presents the determination of the levels of some biochemical constituents in cold stressed P. ricini larvae. Section (3) deals with the evaluation of the activities of some key enzymes such in P. ricini larvae exposed to low temperature. Keeping in view the role of acetylcholinesterase (AChE) in mediating nerve impulse transmission, Section (4) was added to demonstrate the impact of cold stress on silk worms and other insects. In order to present the assessment of the impact of cold stress onto the extent of gene expression in the insects, Section (5) exhibits protein profiling of P. ricini larvae exposed to the cold shock below the sub-optimal rearing temperature for a specific time period which demonstrated the appearance of additional protein bands. We are confident that the present book may be of great use to all those interested in knowing response of insects in general and the silk worms in particular.