The Sycamore Lace-Bug 7 



To illustrate : The following indicates the number of eggs laid by 

 a female during a period of several days March 19, 6 eggs; 

 March 20, 12 eggs; March 21, 4 eggs; March 22, 9 eggs; March 

 23, 2 eggs ; March 24, 1 1 eggs ; March 25, 4 eggs. Some inter- 

 vening days no eggs will be laid at all. 



Flight of the Adults 



The mature insect, when disturbed, will make short flights, 

 darting about in a zig-zag manner. The flying wings are delicate, 

 membranous structures, not strong enough for flights of great 

 duration. The wing covers are extended at right angles and vi- 

 brated rapidly; they serve as balances for the insect while it is 

 flying. 



Life Cycle 



The breeding experiments conducted by the writer were car- 

 ried on in the insectary during March and April before the syca- 

 mores outside had put forth leaves, and while not exactly repre- 

 senting natural conditions, they should approximate quite closely 

 the average growing conditions in Oklahoma throughout the sum- 

 mer. (See accompanying figure with curve showing the mean 

 temperature and humidity for this period.) 



It was found that temperature was an important factor in the 

 time required for the hatching of the egg as well as the time 

 necessary for each nymphal stage. The eggs hatch in from 

 fourteen to twenty-one days. Under optimum conditions they 



Figure 2 Curve showing humidity and temperature maintained in insectary during 

 life history studies; a, temperature curve; b, humidity curve (original) 



