if on poor land and during dry weather, checking their growth 

 and causing the foliage to turn yellow. 



My previous experiments in rearing the species were in some 

 res|H'cts unfortunate, in being interrupted, although there was 

 some profit attached to the failures. The results, as well as the 

 whole series of experiments, as they were carried out, are here given. 



Infested wheat plants were taken from the field and j^laced in 

 breeding cages, out of doors, .April 5th. May 6tli., from what 

 appeared to be the second generation from the individuals from 

 the fields, two pup;e were selected and isolated on wheat plants. 

 On the 8th both began reprotlucing, but only one of them was 

 retained, the other being destroyed. The retaineil female i)r()duced 

 Cwt young between 7.30 A. M. and 5.30 1*. M. of the 8lh, and 11 

 more v\p to 7.30 A. M. of the 9th. Six young were found on the 

 morning of the loth, five on the morning of the iitli, three on the 

 morning of the 12th and three on the morning of the 13th, but the 

 mother was nowhere to be found, she eviilently having escaped 

 from under the glass with which the plant was covered. Her pro- 

 geny of the 8th, five in number, had been kept on a separate i)lant 

 under another cover, and these, except one which was killed by 

 accident, reached the adult stage on the 15th. Two of these were 

 winged and two were wingless, and one of each produced young as 

 follows : 



May 15, winged female had produced o and wingless 8 young. 

 " 16 " " " '' o " "11 ■' 



"17 " " " " 7 " "7 



"18 " " " " 3 " " 8 



19 " " " " 2 " "7 



" 20 " " " " 3 '• "5 



21 " " " " 2 " '* 10 



-> '> 



3 " " 9 



" 23 I " " ' 



" 24 " 3 " 



'• 25 " " " " o 



" 26 " " " " o 



The winged female died on the 261I1, after producing 24 young 

 in twelve days. The wingless female escajjed on the 23rd, after 

 l^roducing 65 young in nine days. 



Females were again secured and produced young on June 

 2nd, after which the parent was destroyed, the progeny themselves 

 giving birth to young on the 8th. .\ wingless female was selected 

 and reproduceil as follows: 



