THE CHAFF SCALE OF THE ORANGE. 39 



ill fall may be assumed to be approximately coiitempoianeous with those 

 of the Loug Scale. Tbey occur iu March or April and in September or 

 October. These months are therefore the proper ones for treatment 

 with remedies. 



Habitat. — The Chalf Scale infests by preference tli<' tiiink and larger 

 branches, and to these it tienerally confines itself until every portion of 

 their surface is thickly coated, and the young Bark -lice can no longer 

 find places to plant themselves. It is also frequently seen upon the fruit, 

 occupying the pit-like depressions of the rind. This habit, combine*! 

 with its light color, renders it inconspicuous upon the fruit. Upon the 

 trunks of trees, also, its resemblance to the bark causes it to escape 

 notice, so that many ])ers(»ns whose groves are suffering from the at- 

 tacks of this scale are unaware of its presence. 



Food-plants and Origin. — Ithas4ieen found upon various plants grow- 

 ing near infested orange trees. Japonicjis and similar thick-leaved 

 plants sometimes sutler severely from its attacks. It is not known to 

 infest any native wild plants, and is not found -upon the Wild Orange, 

 except in the immediate vicinity of cultivated plantations. It cannot, 

 therefore, be considered a native insect, nor is anything known with 

 certainty concerning its introduction. 



Professor Glover, in his report to the Commissioner of Patents 

 for the year 1855, mentions the introduction in that year of a Scale- 

 insect, which he says was inii)orted into Jacksonville, Fla., on some 

 lemons sent from Bermuda. This Scale-insect has been stated to be 

 Mytilaspia citricola. Fron> the brief description given by Glover, it is 

 not possible to determine with ceit;iinty the species referred to, but the 

 small size and shape of the female and the white color of the male scales 

 agree closely with the species now under consideration, and render it 

 lU'obable that the Chaft" S(;ale, and not the Purple Scale, was the insect 

 in question. 



Parasite.^. — In addition to many external enemies, a single Hyme- 

 nopterous parasite attacks this scale, and is a very efficient destroyer of 

 the species. It is a larger insect than those found in the scales of My- 

 tilaspis, and its larva does not live within the body of the Coccid, as is 

 usual with these minute parasites, but originates from an ef!;g de])osited 

 beneath the scale and among the eggs of the Scale-insect, which is al- 

 ways of adult size when attacke<l. The grub of the parasite makes 

 room for itself as it grows by eating lirst the eggs of its host and then 

 her body. Sometimes, indeed, the eggs alone of the Coccid api)ear to 

 suffice for its sui)port and the motlM'r Bark-louse is not molested. 



The pupa of the parasite is formed uiuler the scale, and altliough 

 without cocoon or coverings of its own, is surrounded by the dry skin 

 and egg-shells of the Bark-Ionse. 



The tiy issues through a round hole which it eats in the top of the 

 scale. 



