166 B. C. Entomological Society 



In looking over specimens of the Oj^stei" shell scale in search of 

 examples of the Hemisarcoptes, there will be found no external evidence 

 of their presence, but, on the scale being inverted, the appearance of the 

 eggs, if attacked, is quite characteristic. Even if no mites are found, 

 a number of empty eggshells being in evidence with a certain percentage 

 of injured eggs of a shrivelled appearance lying in confusion, the mites 

 being found amongst these, and also scattered amongst the undamaged 

 eggs. 



The mites are shining white in colour, and are approximately of the 

 same size as the eggs of the scale insect. The body is oval in outline ; 

 the legs, eight in number, are provided with "tarsal suckers," which are 

 of service to the creature in walking over slippery surfaces; there will 

 be found arising from the hind tarsi a number of long hairs, which are 

 dragged along by the mite in its wanderings ; these hairs are evidently of 

 of some service to the mite in enabling it to find a foothold, the. hairs 

 being closely applied to the surface upon which the mite is resting, even 

 an inverted plate of glass appearing to offer no obstacle to their progress. 

 It is a well-known fact that this mite is never to be found beneath old, 

 empty scales, but is always discovered in the presence of healthy eggs, 

 or under those scales harbouring the parent female, for it appears, from 

 the observations of Ewing, Webster, and A. R. Baird (Tothill, 1. c. p. 

 194), that the Hemisarcoptes feeds also upon the parent scales themselves. 

 From the above facts, and also from the appearance of the mite when 

 compared with certain species of scavenger mites, also found in associa- 

 tion with the oyster shell scale, the matter of identification is not a diffi- 

 cult one. The number of mites to be found beneath a single scale varied, 

 in those examples examined at Vernon, from a single adult to six or 

 seven individuals, both adults and j'oung nymphs ; the latter being pro- 

 vided with only six legs, mature specimens possess eight in all. The eggs 

 of this mite are deposited beneath the caudal margin of the scale, and 

 occurred in numbers varying from six to fourteen in those cases noted at 

 Vernon. Individual eggs are somewhat less than half the size than the 

 eggs of the scale insect, shining white in colour and oval in outline. 



The maximum jieriod of oviposition of tliis mite appears from local 

 observations to be during April and May, although eggs have been found 

 during the entire summer. Lignieres, in his observations on the oviposi- 

 tion of the mite in Prance, states that eggs were found at all seasons of 

 the year, the minimum number being found from November to January. 

 Ewing and Webster, in their Iowa observations recorded in "Psyche, 

 Volume XIX., No. 4," noted a similar set of conditions to the above, find- 

 ing eggs and mites numerous beneath the scales on March 29th, and also 

 during April and May. 



Local notes at Vernon are quite incomplete as regards the period of 

 oviposition ; no eggs were found during March, the first eggs noted being 

 on April 14th. 



