THE TURTLE-BACK SCALE. 51 



sites are, as usual, minute Hymenopterous flies belonging to the family 

 of the Chalcididcc. The destruction which they work upon colonies of 

 the Bark-louse is so great that frequently it appears an accident due to 

 oversight on the part of the parasites if among the throng an occeasional 

 individual Coccid escapes. Among scattered and solitary individuals of 

 Lecanium the destruction by parasites is less complete and many escape. 

 If it were to remain strictly gregarious at all seasons of the year this 

 now common Bark louse would no doubt speedily become a rarity. The 

 following four species of these parasites have been observed to prey 

 upon Lecanium liexpcridum : 



Coccophagu* lecanii (Fitch). In this species the general color of the 

 body is black, the crescent-shaped shield on the back between the 

 wings is lemon yellow in the female and brown in the male; eyes dark- 

 red brown ; anteniuB light brown, with the tip of the club darker; 

 wings clear, with dark-brown veins; thighs brown, yellow at the ex- 

 tremities, the remainder of the legs light yellow, with the last joint of 

 the tarsi brown. The length varies from I 1 "" 1 (0.04 inch) in the female to 

 0.5 min (0.0-J inch) in the male. 



This parasite lives upon several species of Bark lice, and is found in 

 all parts of the United States. In Florida it is the most common para 

 site of Lecanium hesperidum, and is seldom absent from its colonies. 

 With rare exceptions a solitary specimen of Coccophagus occupies the 

 body of each parasitized Lecanium. The Coccids are always attacked 

 before they attain full growth. In dying they turn black and adhere 

 firmly to the bark. The bloated and hardened skin of the Bark-louse 

 forms a casket in which the parasite undergoes its transformation to a 

 pupa of dark color, and from which it emerges in time as a perfect tiy 

 t hrough a round hole eaten in the shell. If there are any distinct broods 

 they coincide with those of the Bark-louse, and with the colonies of the 

 latter the numbers of the parasite increase or diminish. 



Coccophaguscognatm Howard (Fig. 12) 

 is a somewhat larger species than the 

 preceding, rather lighter (dark brown) 

 in color. In the female the shield upon 

 the back is orange-yellow ; in the male 

 the corresponding parts are tipped with 

 light yellowish-brown. The front legs 

 are fuscous, the middle and hind pairs 

 darker; all the tarsi are whitish, with 

 the last two joints dusky. Length of 

 female 1.2 mm (0.05 inch), of male 0.6'p 

 (0.02 inch). This species, first noted Fl - i2.-Coccopjo.7 oognatut. (After 



l Howard ) 



and described by Mr. Howard (Report 



of Commissioner of Agriculture for 1880, p. 359), was bred from Lecan- 

 ium licsperidiim on orange trees in the orange house of the Department 

 of Agriculture at Washington. 



