THE ARGENTINE ANT IN RELATION TO CITRUS GROVES. 17 



It is worth noting here that the sweet seedling trees of Cameron 

 Parish, which are apparently of Sicilian origin, are much more re- 

 sistant to these scales than the budded trees. Although the more 

 important scales occur on this type of tree, the infestation is always 

 very light. The citrus white fly, likewise, has not become a pest on 

 the Sicilian seedling trees, and these appear to be especially well 

 adapted to the conditions found in southern Louisiana. 



The status of other armored scales of citrus occurring in Lou- 

 isiana is about as follows: The Florida red scale, which Morgan 

 noted as occurring only at New Orleans and Southport, 1 just across 

 the river, in 1893, is now found scatteringly throughout Orleans, St. 

 Bernard, and Plaquemines Parishes on citrus, palm, banana, olean- 

 der, privets, camphor, and other trees. It never has been of more 

 than very minor importance. The California red scale (Chrysom- 

 phalus aurantii Mask.), a very serious pest in parts of southern Cali- 

 fornia, has been reported on an ornamental tree (Podocarpus ja- 

 ponica) in Audubon Park, New Orleans, 2 and has been observed 

 there by the writer, but does not occur in the orange groves. 



The Ant Does Not Attend the Armored Scales of Citrus. 



The armored scales do not excrete honeydew or any similar liquid 

 attractive to the ants, and are not, therefore, attended by the latter. 

 On the contrary, they probably would become the prey of the ants 

 if it were not for their protective shield or scale. Many hours of 

 observations, extending over a period of nearly three years, on the 

 actions of the ants toward the armored scales have shown conclu- 

 sively that they do not directly attend the scales either in the ex- 

 pectation of receiving honeydew or of capturing emerging parasites, 

 which, by the way, are neither numerous nor effective. In the course 

 of these observations ants several times have appeared to be palpat- 

 ing armored scales with the antennae, but on closer examination the 

 real subject of their attentions always has proved to be a young mealy- 

 bug or other soft scale resting close to the hard scales. The pre- 

 dominance of the armored scales makes impossible that their attend- 

 ance should escape notice if it occurred. 



It was discovered early that ant shelters sometimes occur over 

 large and small groups of the diaspine scales, but this activity could 

 not afford protection of the least consequence to these scales, for 

 the number thus covered is infinitesimally small in comparison with 

 those not covered. That even those scales under the shelters receive 

 only dubious protection from them is shown by the fact that they 

 are often infected with some of the prevailing scale fungi. The fre- 



1 See Stubbs and Morgan, op. cit., p. 60. 



2 Barber, T. C. Tbe scale insects of Audubon Park. In Jour. Econ. Ent., v. 4, p. 450. 

 1911. 



