138 U.S. NATIONAL MUSEUM BULLETIN 256 



bugs {Pseudococcus Westwood) have been recorded on cactus plants 

 on various occasions and from various localities, but their restriction 

 to cactus plants has not been ascertained and, at least in some cases, is 

 very doubtful. 



Homoptera: Coccidae 



DACTYLOPIUS Costa 



This genus, as at present defined, contains several species and is re- 

 stricted to the cactus family. Indeed, the various forms are almost wholly 

 confined to the genus Opuntia and the closely allied Nopalea. The only 

 exceptions to the last statement of wliich we are aware are records of 

 cochineal, either Dactylopius indicus-ceylonicus or the South American 

 form of D. confusus, on Cereus aethiops and Echinopsis intricatissima in 

 Argentina. 



COCHINEAL insects: HISTORY 



The name "cochineal" is familiar to everyone as the crimson dye which 

 is obtained from the insects' bodies. All species produce this coloring 

 matter, but only D. coccus has been used commercially for this purpose. 

 This insect, variously termed the true cochineal, the cochineal of com- 

 merce, or "grana fina," is the largest species and hence produces a 

 greater quantity of the dye substance, which is said to be of a better 

 quality than that obtained from the other forms. 



When the Spaniards conquered Mexico in the 16th century, they 

 found the cochineal industry well established by the Aztecs. Indeed, 

 according to A. von Humboldt, its cultivation appeared to have been 

 maintained for hundreds of years. It remained an important pursuit 

 after the conquest; in 1802, more than 3,000,000 pounds of cochineal 

 were exported through Vera Cruz. The Spaniards established the 

 insect in the Canary Islands, where the industry reached its highest 

 development about 1876, when the world crop amounted to about 

 7,000,000 pounds per annum. The discovery of aniline dyes brought 

 about the decline of the industry, but the production of cochineal is 

 still firmly established in the Canary Islands, although on a greatly 

 reduced scale. 



The introduction of prickly pears to such countries as India, Ceylon, 

 South Africa, and Australia in the 18th and the early years of the 19th 

 century was due primarily to the desire to establish the cochineal in- 

 dustry. Lack of knowledge regarding the different species of these insects 

 and the types of Opuntia or Nopalea suitable to D. coccus resulted not only 

 in the acclimatization of D. ceylonicus in India and Ceylon and of D. 



