326 



THE GYPSY MOTH. 



third molts, were placed in corked vials without food, and 

 kept in a normal temperature, in order to see how long they 

 would live under such conditions. Observations were made 

 on them at intervals of twenty-four hours. The following 

 table gives the number of caterpillars dying on the specified 

 dates : — 





March 

 21. 



o . 



u 



March 

 23. 



Marcli 

 24. 



March 

 25. 



March 

 26. 



March 

 27. 



March 

 28. 



March 



2;). 



o . 



t-l o 

 c3 CO 



Total. 1 



Just hatched, . 







5 



8 



12 



- 











25 



First molt, 







1 



11 



13 













25 



Second molt, . 









7 



9 



9 











25 



Third molt, . 









9 



7 



3 



1 



3 





2 



25 



This shows that caterpillars in the earlier stages will 

 readily live four days without food ; that an appreciable 

 number of second-molt caterpillars will live under the same 

 conditions for five days, while the third-molt caterpillars 

 may exist on starvation diet for nine days. 



To gain further knowledge of the period of time it is 

 possible for gypsy moth caterpillars to live without food, 

 a number of them were placed in cold storage, and a few 

 removed from time to time and supplied with food. For 

 this work, which was carried on during the month of April, 

 1895, use was made of a double box packed with sawdust 

 and stored in a refrigerator, the temperature of which 

 averaged about 40^ F. The caterpillars were kept in corked 

 vials and removed as needed. At the ordinary tempera- 

 ture of the refrigerator the caterpillars became rigid and 

 inactive, and remained so throughout the time involved in 

 the experiment. April 3, 1895, a number of caterpillars in 

 each of the difierent molts, from those just hatched to those 

 between the fourth and fifth molt inclusive, were placed, with- 

 out food, in corked vials in the refrigerator box. All of 

 those between the fourth and fifth molt died within a day 

 or two, possibly due to contact with the large quantity of 

 saliva which they ejected soon after being placed in the box. 



