CACTUS-FEEDING INSECTS AND MITES 147 



States and semitree and tree pears in Mexico. The following list 

 indicates the species of prickly pears attacked : 



United States: texas: 0. lindheimeri, cacanapa, engelmannii, phaeacantha, 

 macrocentra, atrispina, and aciculata. new Mexico: 0. engelmannii and 0. phaea- 

 cantha. ARIZONA: 0. engelmannii, phaeacantha, and their various relations; and 

 0. toTtispina types (dwarf pears). California: 0. littoralis. 



Mexico: 0. streptacantha, megacantha, hyptiacantha, leucotricha, robusta, mac- 

 dougaliana, fuUginosa, tomentosa, fwus-indica, and cantahrigiensis. 



In Australia, D. opuntiae has been reared on 0. inermis, 0. stricta, 

 0. dillenii, 0. nigricans, 0. elatior, 0. monacantha, and 0. miaodasys; and on 

 Nopalea dejecta. With the exception of 0. inermis, these forms are not 

 found within the insect's range in the United States and Mexico. 

 0. inermis is indigenous around Galveston, Texas, but cochineal has 

 not been observed on any species of prickly pear in that vicinity. 

 Records of cochineal on the small low- growing Gylindropuntias of 

 the ciavatae series, viz., 0. stanlyi in Arizona and 0. grahamii in Texas 

 and Mexico, have been referred to D. newsteadi. It is possible that D. 

 opuntiae, as well as D. newsteadi, may attack certain Gylindropuntias. 



Dactylopius confusus Cockerell 



According to T. D. A. Gockerell (1929, in litt.) this species is common 

 in the Rocky Mountain districts of Golorado and Texas. In the present 

 paper, the cochineal prevalent on the low-growing Platyopuntias 0. 

 tortispina, . polyacantha, and their allies, in the more northerly sections of 

 the United States is deemed to be D. confusus. The Prickly Pear Board 

 has recorded infestation on 0. tortispina types in Oklahoma and 

 Colorado and in Kansas and Nebraska, and on 0. polyacantha in 

 Golorado, Wyoming, and Utah. In July 1926 cochineal was com- 

 monly observed on 0. polyacantha from Denver, Golorado, to Gheyenne, 

 Wyoming. Material found on the low-growing 0. hasilaris at Lees 

 Ferry and the Grand Ganyon in northern Arizona probably represents 

 this species. 



In Florida, where D. opuntiae has not been found, D. confusus occurs 

 everywhere. It is especially prevalent on the northeast coast between 

 New Smyrna and the border of Georgia and is common in southwestern 

 coastal areas. Moreover, the host plants include not only low-growing 

 prickly pears but also the shrub pears 0. stricta and 0. dillenii, both 

 of which are commonly attacked. Low-growing forms that are very 

 subject to infestation are 0. austrina, 0. polyacantha, and the narrow- 

 jointed 0. tracyi. In Australia the Florida strain was reared with some 

 difficulty on 0. inermis. 



