Notes on the Green Bug in Texas. 287 



pagating the generation series before No. 2, if alive and doing 

 well, can be safely released from sharing responsibility in 

 the continuation of the generation series. Otherwise, if the 

 need of substitutes in place of No. 1 should require any of the 

 successive individuals, or if No. 2 alone should fail, the start- 

 ing of the individual series must be postponed until genera- 

 tion 3. or, if necessary, until a further one has advanced far 

 enough to allow the serial separation of the desired indi- 

 viduals. 



Continue this special breeding of serial offspring by selec- 

 tions from the generation series until each differently num- 

 bered individual has been treated for whatever purpose in- 

 tended. In explanation, this statement does not mean, when 

 in case No. 2 of generation 2 is used that No. 3 need be of the 

 same generation, but rather of the following generation, and 

 so on for all the numbers. However, should the matter of sav- 

 ing time be an object, provided that facilities for isolation are 

 ample, two or three numbered individuals of a generation may 

 be treated at one time with little risk of the results being at 

 any material variance with results in case of similarly num- 

 bered individuals from different generations. 



Whenever an individual has been carried as far as desired, 

 or when the young are not wanted for this particular breeding, 

 remove the superfluous bugs to a general stock cage or destroy. 

 The stock cage is needed to furnish a supply of bugs for ex- 

 periments with predators, and, when possible, with parasites; 

 also for tests with different host plants, and for use in other 

 ways including general observations. 



PROBABLE INFLUENCE OF HOT WEATHER UPON THE 

 GREEN BUG. 



The experimental breeding of Toxoptera gramium during 

 the summer months was somewhat disappointing in the out- 

 come by not producing any change of form from the serial 

 wingless viviparous females. In the stock cages, however, 

 winged females appeared to constitute a moderate and fairly 

 uniform proportion at all times in comparison with the pre- 

 dominant number of wingless females. The probable influ- 

 ence ot hot weather culminated in no discernible effect except 

 upon the fecundity of the bugs in the serial breeding. 



Three or more factors, whose separate or combined influ- 

 ences might possibly have been exerted on the breeding of the 



