148 U.S. NATIONAL MUSEUM BULLETIN 256 



Cochineal appears to be more abundant in Florida than in any other 

 portion of the United States and Mexico. Cultures were very numerous 

 in many localities in August 1927, December 1929, and April to 

 December 1932. During the latter period, heavy infestations caused 

 considerable destruction of new growth. 



Dactylopius sp. near conjusus Cockerell 



Two species of cochineal occur in Argentina, D. ceylonicus and the 

 undetermined form near the North American D. conjusus. Their dis- 

 tribution overlaps, and their range of host plants includes some of the 

 same prickly pears. D. ceylonicus is the less woolly species. Hence, field 

 determinations have been made with some degree of certainty. 



The ncar-confusus species of Dactylopius is quite prevalent in central 

 and western Argentina, in the Provinces of Santiago del Estero, die 

 Chaco, Salta, Tucuman, Catamarca, La Rioja, San Juan, Mendoza, 

 and Cordoba. The usual host is the low-growing, thick, and rather 

 large-jointed 0. sulphur ea, which is common throughout these Prov- 

 inces. The narrow-jointed prickly pears 0. utkilio and 0. discolor are 

 infested, but not as freely as by D. ceylonicus; and the insect breeds 

 readily on 0. aurantiaca. The mound prickly pears of the Tephrocactus 

 group, 0. weberi, 0. russellii, and O.wetmorei, are also attacked. Cochineal 

 on Cereus aethiops and Echinopsis intricatissima in the province of Mendoza 

 very probably represented this species. The tree pear 0. quimilo and the 

 many shrub pears of the 0. monacantha type have not been recorded 

 as food plants. 



Observations in the Provinces of Tucuman and Santiago del Estero 

 indicate that cochineal is most abundant in April and May; its num- 

 bers decrease during winter; in August to November the infestation 

 is light and scattered, and then gradually increases during summer. 

 Natural enemies play an important role in controlling these insects. 

 Heavy infestations are not uncommon on 0. sulphurea in January to 

 March in Mendoza and the adjacent provinces; in the case of a severe 

 attack, the 0. sulphurea joints often become deformed to some extent 

 and produce many small joints from the lateral areoles; this ab- 

 normal growth is in turn freely attacked and is frequently destroyed. 

 In March 1921 many clumps of 0. wetmorei were severely damaged 

 at Tunuyan, Mendoza. 



Dactylopius ceylonicus Green 



This species is found in southern Brazil, Uruguay, and over a wide 

 area in Argentina, from Entre Rios to Cordoba, Catamarca, Salta, 

 and the Chaco. It commonly attacks three distinct types of Platyo- 



