48 GRAPE CULTURE AND 



small, live, fertile winged phylloxera, and was transferred to 

 a small vial, where she laid a single egg and died. Others of 

 these pupae were found later without much difficulty on simi- 

 lar roots ; and others of the winged form have since been 

 easily developed. Their changes during metamorphosis into 

 complete forms were watched with exceeding interest, but 

 need not be described here. 



Some of the insects which were most developed, and had 

 the wing-pads well formed, were placed upon a glass slide, 

 covered with a watch glass, and then properly arranged under 

 a microscope. The transformation soon took place. A shed- 

 ding of the skin precedes the spreading of the wings, 

 and is begun by the dark skin separating horizontally over the 

 wing-pads, a part shedding toward the abdominal segment, 

 and the remainder passing over the head and legs, thereby 

 changing these members and the antennae to a much lighter 

 color. This operation, in one case, was completed in about 

 fifteen minutes. The wings, which appeared to be folded in 

 a light colored bunch directly across the back, now part in 

 the middle, giving them the appearance of two white or light- 

 colored sacks. These gradually expand laterally from the 

 base, continually carrying the apparent casings in a bunch at 

 the end of the wings until the full length is reached, after 

 which the greater part of the spreading is done. The whole 

 apparent casings are merely folded wings. 



One hour and fifteen minutes was consumed in passing 

 from the beginning of the shedding of the skin to the com- 

 plete winged insect, which soon became active and began 

 crawling abou*-. The body of the insect, in the meantime, 

 had passed from a light hue to a more intense dark yellow, 

 or golden color, while the wings, which before the moulting 

 were black, pass to a light or white opaque, then become 

 transparent, and, as they spread, become thinner and darker, 

 and in the fully developed condition are almost black. 



