THE CANADIAN ENTOMOLOGIST 315 



white when laid, but change to cream yellow previous to hatch- 

 ing. 



The young larvae measure .37 mm. in length and .135 mm. 

 in width and are pale yellow, with eight distinct abdominal seg- 

 ments, but with no definite body divisions. The antennae are 

 short, six segmented, with numerous long setae. Two anal plate 

 spines are conspicuous, being about one-third the length of the 

 body. After settling the insects assume a transparent green colour 

 and are practically invisible on the surface of the leaf. 



The second stage" larva is distinguished microscopically from 

 the first by the absence of the major apical setae which disappear 

 at the first moult. Upon migrating to the bark the green colour 

 is replaced by brown. In this stage two sizes become differentiated, 

 the larger measuring about one mm. in length, and the smaller .7 

 mm. 



The puparium is a rather elongate oval structure 1.5 mm. in 

 length and .75 mm. in width, the white, glassy colour sharply 

 contrasting with the bark. It is slightly convex and is adorned 

 by two longitudinal and two transverse white lines. (Plate, XV, 

 fig. 6.) These scales are fragile and the empty ones are easily 

 dislodged, seldom being found later in the season. 



The adult male is a small, brown, two-winged insect 1}4 mm. 

 in length, with a wing expanse of 4 mm. and having two long, 

 white caudal filaments. The antennae are relatively large, eight 

 segmented, and densely clothed with hairs. The head is pro- 

 vided with six ocelli, one pair being located ventrally and two 

 dorsally. (Plate XVI, figs. 12 and 13.) The wings are clouded 

 with a tinge of brown and no halteres are present. There are 

 six segments in the abdomen which terminates in a large style at 

 either side of which are secreted the two long wax filaments. 



At maturity the female' is a smooth, brown hemisphere, and 

 is incapable of locomotion, the appendages having been greatly 

 outgrown by the swollen body which is fastened to the bark by 

 a deposit of wax. (Plate XV, fig. 3.) Microscopically the anal 

 plates (Plate XVI, fig. 10) are conspicuous and obtusely triangular, 

 having eight anal ring setae, four fringe, two sub-apical, and eight 

 apical setae. Fully mature females still possess the appendages 

 though in an atrophied form, and may measure from 3 by 2 mm. 



