116 INSECTS AFFECTING VEGETATION 



geometrical pattern. It was long known from Florida, where it is 

 undoubtedly native, its principal food plant being the gall berry. 

 It has now been carried, however, to other parts of the world, notably 

 some of the adjacent West Indian islands, and also to the Old World. 

 It was imported into California on stock from Florida in 1889, and 

 possibly earlier, but has never gained any foothold on the Pacific 

 coast. This insect often occurs on citrus plants, though rarely in 

 sufficient numbers to be of very great importance. The white color 

 and striking appearance of these scales cause them often to be noted, 

 and very natural fears of damage are excited, but as a rule the nat- 

 ural enemies and other causes result in very few of the young reach- 

 ing the adult stage. This, as shown by Mr. Hubbard, not only fol- 

 lows the action of parasites, but also is due to the fact that the scale 

 lice as they become old and gravid can not maintain their hold on 

 the smooth surface of the lemon or orange leaf and fall to the ground 

 and perish. The citrus plants, therefore, are not especially adapted 

 to this insect and very rarely suffer long or seriously from it. 



The Florida wax scale is three-brooded, developments not being 

 very rapid and extending over three or four months. The waxy se- 

 cretions give an appearance to the young insect of an oval stellate ob- 

 ject, the waxy prominences coalescing and disappearing with age. 



The Barnacle Scale. This insect, which is closely allied to the 

 last, has been found in two or three localities in Florida, notably at 

 Jacksonville and in Volusia County, on orange and quince, and also 

 on a species of Eupatorium. It is frequently associated on citrus 

 plants with the Florida wax scale. It has since been found on the 

 same and other food plants on some of the West Indian islands and 

 in Louisiana and California. The barnacle scale is much larger than 

 the Florida wax scale, having an average length of 5 millimeters and 

 a width of 4 millimeters. The waxy covering is a dirty white, mot- 

 tled with several shades of grayish or light brown, and the division 

 of the waxy excretion into plates is distinct, even to a late age. The 

 development of the insect and secretion of the waxy scale covering 

 is very similar to that of the last species described. The barnacle 

 scale is of very little economic importance, and is mentioned merely 

 because its presence might arouse suspicions of probable injury. 



The Fluted Scale. Of all the scale insects attacking citrus 

 plants, this species is perhaps the most notable, not so much from 

 damage now occasioned by it as from the problems of control which 

 it has brought to the front and the international character of the 

 work which it has occasioned. 



The facts indicate that Australia is undoubtedly its original 

 home, from whence it was introduced on Australian plants into New 

 Zealand, Cape Town, South Africa, and California at about the same 

 time. The evidence points to its introduction into California about 

 the year 1868 on Acacia latifolia. It is a very hardy insect, will live 

 for some time without food, and thrives on a great number of food 

 plants. In California it spread rather rapidly, and by 1886 had be- 

 come the most destructive of orange scale pests. The damage occa- 

 sioned by it was of such a serious character as to threaten the entire 



