Notes on Insect Bionomics. 363 



Note I — Bottom of bottle in which larva was confined was 

 lined with threads May 26; threads extended up one side May 

 27; threads swung across bottle from side to side May 28, and 

 larva actively spinning very damp threads; on May 29 larva was 

 spinning a closely woven circular carpet on bottom of bottle, and 

 on May 30 larva pupated on this carpet (no cocoon). 



Note 2 — Bottom of bottle lined with threads May 26; larva 

 still slowly spinning random threads May 28. 



Note 3 — Bottom of bottle lined with silk coating May 18. 



Note 4 — Larva lined bottom of bottle with stray threads be- 

 fore dying. 



Note 5 — Slight progress in the spinning by June 6, P. M.; bot- 

 tom of bottle lined with threads. 



From these results it may be said that silkworms may be cut 

 off from a food supply nearly seven days before the normal limit 

 of their feeding time and yet complete their development (spin, 

 pupate and emerge as imago) . These seven days represent a little 

 more than half of the last intermoulting actively feeding period, 

 or about one-ninth of the whole larval (feeding) life. The depri- 

 vation of food for from one to four days seems neither to hasten 

 the metamorphosis nor to modify it appreciably, nor to result in 

 the production of a moth of lessened size or lessened fertility. The 

 larvae deprived of food not more than four days before normal 

 close of feeding time do not immediately spin and pupate, but 

 wait restlessly for the normal time of pupation (approxim^aMly 

 twelve days after the fourth moulting), and then normally spin 

 and pupate. If deprived of food for more than four days and 

 less than seven, the larvas shorten their last intermoulting stage 

 to about seven days, forming, however, a normal cocoon and trans- 

 forming into a normal moth. If the larvae are deprived of food 

 eight days or more before their normal splnning-up time, they in- 

 variably die without forming a cocoon, and in only one case was 

 pupation accomplished. A beginning at spinning (see notes) is 

 made by larvae fed for more than two days after the fourth moult- 

 ing, but no spinning at all is done by larvae deprived of food from 

 the day of fourth moulting or from the first or second day there- 

 after. 



