150 U.S. NATIONAL MUSEUM BULLETIN 256 



are host plants of cochineal. This publication refers all these records 

 to D. newsteadi, although it is possible that D. opuntiae may attack 

 Cylindropuntias as well as prickly pears. Investigations at Uvalde, 

 Texas, showed that cochineal on 0. leptocaulis would transfer to 0. 

 imbricata, although not readily; but it could not be induced to transfer 

 from 0. leptocaulis to 0. lindheimeri, the common prickly pear of the 

 Uvalde district where the 0. leptocaulis infestation was obtained. 

 Cochineal taken on 0. echinocarpa in California infested 0. imbricata 

 without difficulty. 

 Our records of cochineal on Cylindropuntias include: 



United States: texas: 0. imbricata, leptocaulis, and grahamii. new mexico. 

 0. imbricata. Arizona: 0. fulgida, spinosior, stanlyi, and whipplei. California: 

 0. echinocarpa and bernardina. 



Mexico (northern) : 0, imbricata, leptocaulis, kleiniae, and grahamii. 



In western Texas and New Mexico, plants of 0. imbricata are often 

 heavily attacked and considerably damaged. 0. leptocaulis usually 

 escapes infection, but occasionally individual plants support heavy 

 cultures. 0. echinocarpa in California has been observed to carry dense 

 infestations. In October 1926 at Torreon, southwest Coahuila in 

 Mexico, cochineal was quite common on 0. imbricata^ 0. leptocaulis^ 

 0. kleiniae^ and 0. grahamii^ but Platyopuntias in the same district 

 were free from attack. 



DIPLACASPIS Jacobson 

 Diplacaspis echinocacti (Bouche) 



This scale insect has a very extensive distribution and a wide range ot 

 host plants among the Cactaceae. It is not prevalent in the United 

 States, but we have records of its occurrence on Opuntia lindheimeri 

 in Texas and on the Cylindropuntias 0. imbricata in New Mexico and 

 0. echinocarpa in California. It is rather generally distributed on the 

 Central Plateau of Mexico, where heavy infestations have been observed 

 on 0. streptacantha in the general vicinity of Mexico City; various 

 Platyopuntias and Cerei are attacked. 



The species is generally distributed through the West Indies on various 

 Platyopuntias and Cylindropuntias; Nopalea cochenillijera has been 

 observed as a host plant in Trinidad. This scale has been seen on prickly 

 pears in Colombia and Peru. 



In April 1921 it was causing considerable damage to Cereus, Opuntia^ 

 and Rhipsalis in the Botanic Gardens at Rio de Janeiro, Brazil. 



D. echinocacti is not uncommon on Opuntia aurantiaca in the Province 

 of Entre Rios, Argentina. In the central and western Provinces of 

 Argentina it is prevalent and attacks Pilocereus, Cereus, and such forms 



