160 



NATURE-STUDY REVIEW 



[6:6-Sept..l910 



also a very full description of the caterpillar when full-grown 

 and ready to pupate. How they behave when preparing to spin 

 and the length of time required to finish the cocoon. The 

 appearance of the cocoons, of which a few should be opened to 



COCOON OF POLYPHEMUS, OPENED TO snOW CHRYSALIS 

 NOTE WING-CASES AND ANTENNAE 



observe their texture and thickness and also to note the length 

 of time required for the transformation from larval to pupa 

 state and the color and shape of the pupae. 



Polyphemus is generally single-brooded in the northern 

 states, and even in southern latitudes the occupant of a late- 

 spun cocoon will remain snugly enclosed until the coming 

 spring. It should be remembered that naturally these cocoons 

 lie among the dead leaves on the ground, or occasionally cling 

 to the twigs all winter, exposed to rain and snov/ and all ex- 

 tremes of temperature. This does them no harm, on the con- 

 trary, they die if kept too dry and warm, and if indoor preserva- 

 tion is attempted, the cocoons should be dipped in water about 

 once a week. A better way is to enclose them in a box and tuck 

 them away in some open shed or under some bush out-of-doors, 

 taking them in about the beginning of May before they feel 

 spring's call to come out. 



The cocoon of the polyphemus being spun with an un- 

 broken thread, the moth must make an opening for itself when 

 emerging. This is done by wetting the case with an acid liquid 

 which it secretes in its mouth for the purpose and then pushes 

 its way out through the threads. Its appearance when first 



