50 JOURNAL OP^ ECONOMIC ENTOMOLOGY [Vol. 10 



In the case of pupa) kept under cover in the insectary it was found 

 that darkness retarded emergence. On a day when it was raining at 

 intervals, moths were observed emerging with the sunny spells when 

 the inverted box was removed from over them. 



A pupa which was at the stage ready for pupation, was brought into 

 the laboratory and induced to emerge by subjecting it to the rays of 

 an arc light. . 



Stages of Emergence 



Stage 1. It was observed in the case of pupae which would emerge 

 on a certain day that there was a small tear across the top of the cocoon 

 which indicated in advance which ones would be likely to emerge that 

 day. Pupse having such a tear would likely emerge that day though 

 unfavorable weather conditions would cause emergence to be post- 

 poned until conditions were again favorable. When a tear was not 

 observed until after the normal time of emergence the insect would 

 not pupate until the next day. 



Stage 2. If one will observe a pupa, as described for stage 1, at 

 the right time (8 to 9 a. m.") on a clear day, the rift across the top of 

 the pupal case will be observed to suddenly widen and the pupa will 

 be seen pushing steadily out of the case until it is about one-third way 

 out. This only requires on an average about 2j minutes. Following 

 this the pupa rests for a period of about twenty minutes before under- 

 taking the next stage of its emergence. 



Stage 3. Following this rest comes another pushing upward fre- 

 quently accompanied by a sort of circular, twisting movement. By 

 this time the pupa has pushed itself from one-half to two-thirds way 

 out of its case. Frequently when they have gotten on this far pupae 

 will be observed going through this circular, twisting movement which 

 Cory noted in his observations. In doing this a pupa may twist itself 

 out of its cocoon, in which case emergence from the pupal skin seems 

 to be difficult. The second stage of emergence requires about five 

 minutes. 



Stage 4. The pupa rests only a few seconds after it is two-thirds 

 way out of its case and then starts to push through its pupal skin. 

 One may observe through the pupal skin that all the body seems to 

 be crowded forward in order to exert as much pressure as possible on 

 the back of the thorax. In the case of females the bright orange band 

 on the abdomen will be observed to move one segment forward under 

 the pupal skin. Suddenly the skin splits over the thorax and the top 

 of the meso- and meta-thorax pushes out, followed by the head. The 

 antennae are then drawn out and are almost immediately followed by 

 the prothoracic legs. This done, the pressure seems to be released 

 and the insect has apparently no difficulty in wriggling out of the skin. 



