746 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



other allied insects. But the instructions previously given as to its 

 manufacture and application must be carried out in the strictest detail in 

 order to ensure success. 



Treatment for Subterranean Mealy Bugs. 



This group of underground coccids belong to the two genera Dacty- 

 lopius and Ripersia. The former contains the typical mealy bugs, the 

 females of which usually possess eight pointed antennae, while typical 

 Ripersia possess but six joints. The subterranean species of both genera 

 are usually much smaller than the arboreal species, but otherwise they 

 do not materially differ. Members of both genera have a world-wide 

 distribution, being found in New Zealand, Australia, North and South 

 America, Africa, and the continent of Europe, Great Britain and the 

 Channel Islands possessing the greatest number of species. The 

 economy of these insects is exceedingly interesting, as many of them are 

 associated with ants in various parts of the world. Mr. W. W. Smith, 

 of New Zealand, has shown that the interrelations of these insects are of 

 great interest. He has found that the presence of these root-feeding 

 coccids forms an economic basis for the origin of ants' nests, and that no 

 less than three species belonging to the genus Huheria almost invariably 

 start their new nests where the coccids have established themselves on 

 roots of "plants under stones. Mr. Smith also tells us that "if a newly- 

 selected site be disturbed by turning over the stones . . . the coccids 

 will occasionally leave it and the ants will disappear with them." 

 Further, that he has seen ants " seize a coccid and carry it about the 

 nest apparently merely to protect it. . . . When a portion of a gallery 

 is formed or any interstices occur among the small stones in the site, the 

 ants carry and deposit the coccids in such places of safety ; in old 

 communities they are borne into the inner galleries to be carried out to 

 the courts of the nest when all danger is past." 



In this country we have not been able to ascertain whether ants 

 establish their new nests with root-feeding coccids ; very probably they 

 do. But their behaviour to the coccids in their nests in many instances 

 has been found to be much the same as observed by Mr. Smith. If a 

 nest be disturbed, the ants in many instances have been seen to carry off 

 coccids to a place of security ; but in some few instances the ants have 

 not shown any signs of attachment to them. As "mealy bug" are 

 known to secrete a sweet fluid, like the honeydew of the aphides, it is 

 highly probable that these subterranean coccids possess the same power. 

 And if this be so it would account for the interrelation, or perhaps the 

 interdependence, of these insects. 



The chief object of this communication is to call attention to a com- 

 paratively new species of root-feeding " mealy bug " {Bipersia terrestris, 

 Newst.), which was described from specimens found infesting stephanotis 

 roots near London in February 1895. Shortly afterwards it was also 

 found in the same district on the roots of Palms. Quite recently the 

 species has also been found infesting the roots of Adiantum (fig. 314) to 

 such an extent as to produce a marked effect upon the foliage of the- 

 plants, causing it to turn brown, as in plants too much dried at the roots. 



