Notes on the Green Bug in Texas. 2S9 



Attempts to breed the bugs in the open sunshine eventually 

 proved unsuccessful. These tests, however, demonstrated the 

 hardiness of the bugs in withstanding a few days of exposure 

 to sun heat, and then the failures were evidently induced by 

 the wilting or scorching of the food-plants rather than to the 

 direct effect of heat on the bugs. In one case, as long as the 

 plant remained in a fresh condition an adult bore young, and 

 all seemed to thrive for a few days in spite of being enclosed 

 in a glass globe, which subjected both the plant and its ten- 

 ants to a temperature several degrees higher than would have 

 been the condition if the colonized plant were openly exposed 

 to air. This test was made on a bare space of ground wholly 

 unprotected from the sun during the hottest and dryest days in 

 the last week of August, and it met disaster from the baking 

 heat of the first day of September. 



Another test giving proof that green bugs can stand more 

 than LOO F. was demonstrated in the field or stock cages. 

 These cages were constructed of wood frames, three feet 

 square by 4 feet in height, covered with muslin cloth on all 

 sides and top, and banked with earth around the bottom edges. 

 Oats or wheat seedlings grown in these cages were colonized 

 with green bugs, which multiplied rapidly at all times. Fre- 

 quent watering of the soil in these cages was necessary to keep 

 the plants in succulent growth, so that in addition to the tem- 

 perature the interior was charged with a high humidity. Al- 

 though the cloth covering subdued the glare of the sun, never- 

 theless the temperature inside probably ranged from lO"" to 15° 

 F. higher than on the outside. 



The experimental results prove that Toxoptera graminum, 

 when provided with suitable food plants and also protected 

 from the baking heat of the sun, is able to live through the 

 summ;3r. This fact in itself indisputably refutes the popular 

 impression that the species in any active form cannot with- 

 stand hot weather under any circumstances. The adverseness 

 of natural conditions during midsummer principally accounts 

 lor the seasonal suppression of the insects, and these influences 

 may rule for a number of years in keeping the pest under 

 control. 



Since no resting stage could be found when the bugs dis- 

 appeared from the fields, the opinion gained common credenct. 



19— Sci. Acad.— 2163 



