660 
J. DAYIDSOX. 
The “ mother queen ” ^ may be found throughout the year 
on infested apple trees in crevices of the bark. It differs 
somewhat from the apterous viviparous female, in that the 
body is stouter, and of a shorter oval contour, and the legs 
and antennje are shorter. She produces living young or 
“ lice,” which collect round her and form a colony. 
The members of the colony secrete a number of white, 
waxy threads from the dermal wax glands, in which they 
become imbedded. The lice moult in due course and in two 
or three weeks become apterous viviparous females (closely 
resembling the queen-mother but smaller), capable of produc- 
ing living young. This method of reproduction continues 
throughout the summer. Towards the end of summer some 
of the lice may develop iuto nymphs with a large thorax and 
two pairs of imperfect wings. These nymphs develop into 
winged viviparous females which may migrate to other apple 
trees and produce new colonies of living young. Reproduc- 
tion goes on in this way until late in the autumn, when sexual 
males and females may be produced. According to Marlatt 
(1897, p. 3), who cites the observations of Howard and 
Pergande, these winged viviparous females, which appear 
about October or November, give rise to a “ true sex genera- 
tion ” of lice, the females of which lay a single “winter-egg.” 
The sexual forms of S. lanigera are rare. They are 
apterous, small in size, and much reduced in structure, the 
mouth parts being atrophied. The oviparous female lays a 
single egg and then dies. The fertilised eggs are laid near 
the base of the tree, and remaining in the cracks of the bark 
throughout the winter, hatch out the following spring, pro- 
ducing larvae which develop into mother-queens. According 
to observations made by Theobald (1897), some of the adults 
migrate into the soil during winter and attack the superficial 
roots, returning to the aerial portion of the tree in spring. 
' Buckton (1860) assigned the term “ queen aphis ” to the immediate 
issue produced from the egg which becomes the foimder of a colony. 
German authors use the terms “Stammutter” and “ Fundatrix.” 
