82 INSECTS AFFECTING THE ORANGE. 



they destroy great numbers of the young lice, assoou as the latter have 

 fasteuedthemselves to the bark, and while their scales are still soft aud 

 thiu. They also creep into the open end of scales which have begun to 

 hatch, and destroy a portion of the eggs. The scales vacated by para- 

 sites, in which have been left convenient open doorways, furnish the 

 Mites with secure retreats and jdaces of deposit for their eggs. Usually 

 the dry and distended skin of the Coccid is left by the parasite, nearly 

 filling the scale, and with a miliute exit hole immediately opposite that 

 in the outer shell. Thus the Mites or their young and eggs are provided 

 with a double envelope separated by layers of confined air, and nearly 

 impervious to liquids. It is, therefore, not astonishing that applica- 

 tions sufficiently penetrating to kill Scale-insects do not reach thelites 

 and their eggs thus protected. In fact the latter very frequently in- 

 crease enormously after an effective application, because the loosening 

 of the scales by the wash enables them to penetrate to and feed upon 

 the dead or dying Bark-lice, and the sui)])ly of food is for a time largely 

 increased. 



To cause a marked increase in the number of the Mites, it is some- 

 times sufficient to loosen the scales here and there upon the trunk and 

 branches which are most thickly encrusted with them, by scraping the 

 bark with a stick or knife blade. This gives the Mites an increased sup- 

 ply of food, and stimulates them to active breeding. The result is 

 often to effectively check the progress of the Scale-insects for the time 

 beiug, although .they cannot be exterminated in this way. The method 

 is not advanced as a practicable remedy, and cannot be made to replace 

 the proper application of insecticides, but from its simplicity it is fre- 

 quently useful as a means of gaining time, when remedies are not at 

 hand. 



Gloyek'.s Orange Mite {Tyroylyphiiti ? (jlorcni Ashmead). [Plate 

 VI, Fig. 5.] — This is the commonest species found among Orange Scale- 

 insects; it is also the smallest species and the most active and rapid in 

 its movements; it is somewhat longer than broad, slightly flattened; 

 in color it varies from pure white to yellowish, and often a i)ale i)inkor 

 flesh-color. This color- variation is due to the varying nature of its in- 

 testinal contents, seen through the semi transparent body. Length 

 about 0.1""" (roVu inch).* 



The eggs are white, aud are deposited either singly oriu small groups, 

 under a tangle of spider's web, among dead scales, &c. ; lurking places 

 in which the white, six-legged young congregate and undergo their trans- 

 formations. 



* The form in most soft-bodied Acaiiua is very changeable, depending upon the con- 

 dition of the animal, whether fnll-fed, or dei)leted by fasting. The fignre of this 

 species on Plato VI represents the shape commonly seen. When emaciated, the sides 

 of thu body become deeply sinnate or lobed, deep pits are formed upon the upper sur- 

 face in front, and several transverse folds in the skin appear to divide the abdominal 

 portion into segments. In plethoric iudivicluals, the distention of the body into an 

 oval sack obliterates every trace of fold or depression upon its surface. 



