27 



so protected by a covering shell or scale, they are as a rule more easily 

 destroyed by fumigation or sprays, and they fall a more ready prey to 

 attacks of predaceous and parasitic insects. All of the species are egg- 

 laying. The Lecaniums and wax scales deposit their eggs in cavities 

 under their bodies, formed by the contraction of the female insects, so 

 that ultimately the mothers become mere shells over vast numbers of 

 eggs and hatching young. The mealy bugs and fluted scale excrete a 

 quantity of cottony fibers, which are stocked with eggs. After a cer- 

 tain amount of incubation, the young hatch and escape from beneath 

 the old parent scales or burrow out of their cottony nests. In trans- 

 formations and general life history, except in the points noted, these 

 scale insects closely duplicate the habits of the armored scales. 



The Black Scale. 



This scale insect {Lecanium olese Bernard— figs. 18, 19, and 20) is nota- 

 bly an olive pest, but it also attacks citrus fruits, and is quite as destruc- 

 tive to the latter as to the olive. It is an insect of world-wide distri- 

 bution, having been an important 

 enemy of the olive and citrus fruits 

 in the Old World as far back as we 

 have any records. It also affects 

 a great variety of other fruits and 

 plants. It occurs more or less in 

 greenhouses, and has undoubtedly 

 been transported to various parts 



of the world upon greenhouse Fig. IS.-Black scale [Lecanium olex): Group of 

 plants as well as upon the various ^^^'^^^< showing natural position and appear- 

 -, . ,,. .^ T,i TT';i vindQ — enlarged 4 diameters (original). 



subtropical fruits. In the United 



States it is especially destructive only on the Pacific coast, and while 

 it occurs generally in Florida it has never there assumed any great 

 importance as an enemy of the orange or lemon. It not only saps the 

 vitality of the plants by the extraction of their juices, but also abun- 

 dantly secretes honeydew, which results in a badly attacked plant 

 becoming thoroughly coated and blackened with the sooty fungus. 



The adult insect is dark brown, nearly black, in color. Its 

 characteristic features are the one longitudinal and the two transverse 

 ridges. Very often the portion of the longitudinal ridge between the 

 two transverse ridges is more prominent than elsewhere, giving a 

 resemblance in these ridges to a capital letter H. The general surface 

 of the bod}^ of this !^cale insect is shagreened or roughened, which will 

 distinguish it readily, under a hand lens, from the allied species, even 

 before the ridges have become prominent. Very fortunately for the 

 citrus grower, the development of this insect is slow, and it has but 

 one brood annually. The j'^oung, however, appear over a very wide 

 interval of time, and this gives the appearance of more than one brood. 



172 



