SPECIES ATTACKING JOINTS EXTEENALLY. 23 



placed at the end of the stalk-like prolongations of the head. The 

 under parts are dark brownish. 



The species has been collected on Opuntia from San Antonio, Tex., 

 to the coast and southward to Brownsville, Tex. It seems to be more 

 abundant in the vicinity of Corpus Christi, Tex., than elsewhere. 

 The injury is not conspicuous. It causes the plants to assume a 

 spotted appearance, but, except where the bugs are unusually abun- 

 dant, the joints recover. It is not a true cactus insect, but has been 

 found upon a variety of other plants. On account of its gregarious 

 habits it could be easily controlled by means of the gasoline torch 

 when it becomes unusually abundant. 



The Cottony Cochineal Insect. 1 

 (Dactylopius confusus Cockerell.) 



The cottony cochineal insect {Dactylopius confusus Cockerell) is 

 easily recognized by the large flocculent masses of pure white wax 

 which covers the bodies. (PI. V, upper figure.) When crushed 

 the bright crimson color of the body fluid runs out and contrasts 

 strongly with the white envelope. These scale insects are found on 

 the joints of Opuntia. frequently in large masses. 



This species is closely allied to the true cochineal insect, Dactylo- 

 pius coccus Costa, which does not appear to occur in the United 

 States. 2 The true cochineal has only a light powdery covering, while 

 the form in the United States is provided with the heavy covering of 

 cottony wax which has been described. 



The true cochineal insect has had a most interesting history. Car- 

 ried to many parts of the world and cultivated with extreme care, 

 for many years the dried bodies of the females yielded a dye product 

 of great importance in the commercial world. It was also supposed 

 to be an important therapeutic agent. 



In A. von Humboldt's Political History of the Kingdom of New 

 Spain, published in 1811, there is a most interesting account of the 

 cochineal industry in southern Mexico. The author relates that there 

 was every indication that the cultivation of the insect had been prac- 

 ticed for many centuries, undoubtedly, even antedating the invasion 

 of the Toltec tribes. During the reign of the Aztec kings the in- 

 dustry was apparently much more important than at the time of 

 Humboldt's observations. As early as 1592 laws were passed to pre- 

 vent the adulteration of the product. In 1802 the exports through 

 the port of Vera Cruz amounted to 3,308,557 pounds. 



The greatest development of the cochineal industry occurred about 

 1870. The decline began at that time on account of the discovery 



1 Order Hemiptera, Family Coceida\ 



2 The records from Florida nod California in Ihe Fernald Catalogue are probably due to 

 importations. 



