THE LESSER CORN STALK-BORER. 19 



ACTIVITY OF THE LARVA. 



The larvae of this species, while very active, even when quite young, 

 are much more so as they become older. They have a habit, when 

 disturbed, of skipping and jumping about, an acrobatic feat which 

 lasts from one to four seconds, during which time they go through all 

 kinds of contortions, frequently throwing themselves clear of the 

 surface upon which they have been placed. Just how this is accom- 

 plished is not definitely known, as it is done almost too quickly for 

 the e/e to follow. However, they appear to bear down with the 

 head and posterior end of the body at the same time, with such force 

 that the impact throws them into the air. On account of this skip- 

 ping habit the larvae are frequently but erroneously termed 

 "skippers." 



That the larvae are resistant to rougn treatment is indicated by the 

 following ordeal through which one was put by the junior author in 

 an effort to photograph it. It was chloroformed for 15 minutes and, 

 being then still somewhat active, was put into 80 per. cent alcohol 

 for 15 minutes more. The next morning it had revived and, except 

 for a loss in the brillancy of its coloring due perhaps to its enforced 

 fast, was as active as before. 



The larvae in all stages spin a silken thread wherever they go, and 

 the younger ones readily suspend themselves by it. 



LENGTH OF PUPAL STAGE. 



The length of the pupal stage varies considerably, as will be seen 

 from Table VII, temperature conditions having a great effect upon the 

 length of this stage. This stage varies from 7 to 1 1 days in July, from 

 7 to 10 days in August, from 8 to 18 days in September and October, 

 and from 19 to 21 days in October and November. The general 

 average from the records of Table VII is 10.16 +days. 



It should be stated that the records obtained during the fall of the 

 year are approximate, as it has been found that the larvae, upon 

 entering the pupation tubes, sometimes do not transform immediately. 



