SPECIES ATTACKING .JOINTS EXTERNALLY, 15 



little work in raking togetner and burning the fallen portions of the 

 plant where they are numerous would serve to hold the insect in 

 check. It' this practice has not been followed, it will still be possible 

 to check injury with some satisfaction either by poisoning the adults 

 or by collecting them by hand. On account of their Large size and 

 sluggish movements and the fact that they are without wings, hand 

 collecting is qo< difficult and will be very effective. This process 

 would generally he preferred to that of poisoning on account of its 

 cheapness. WheE poisoning is practiced, arsenate of lead should be 

 used. It should be applied, in powdered form only, to the young and 

 tender joints, as the adults feed upon no other parts of the plant. 

 The poisoning of these young joints will also serve to control at least 

 one other important enemy of Opuntia, as will be described later. 



A Cutworm. 



On several occasions a cutworm, Chorizagrotis soror Smith, has 

 been found to do considerable injury to Opuntia plants. The damage 

 is greatest in the case of young plantings. The pulp that is exposed 

 in cutting the joints into suitable pieces for planting seems to attract 

 these worms. In one of the plantings at San Antonio, Tex., they ate 

 canals through the underground portions of the plants. They are 

 partial to the varieties of more tender structure. Whenever this in- 

 sect is abundant it will be easy to protect the plants by soaking the 

 portions used for seed for a few minutes in a solution of arsenate of 

 lead, or. if more convenient, the sections to be planted could be dusted 

 with the powdered arsenate of lead at the time of planting. 



Coccidae 



The only other insects which have been found attacking the roots 

 of Opuntia plants are three species of Coccidse, or scale insects. 

 None of these species has been found to be abundant or to have any 

 marked effect upon the vigor of the plant in the localities in which 

 they occur. It is consequently unnecessary to give them further 

 attention. 



SPECIES ATTACKING THE JOINTS EXTERNALLY. 



Chelinidea vittigera Ubler. 1 



The coreid bug, Chelinidea vittigera Uhler, may be readily recog- 

 nised from the following brief summary of its appearance and 

 habits : 



It is a yellowish bug resembling the common squash bug (Anasa 

 tristis De Geer) in general appearance (fig. 1), about 15 mm. long, 



1 Order Hemiptera, Family Coreidse. 



