APPENDIX 



323 



head and prothorax. pigmented eyes and well-marked body segments; on 

 the other, the form is yet more like that of the stem-mother, the head not 

 well separated, the eyes much less marked, and the body segments scarcely 

 distinguishable except at the edges. The embryos in this form are now 

 much larger and more obvious. In both types of this stage the feelers are 

 six-jointed, and much more evidently scaly. There is a little censory pit at 

 the end of the fifth segment and a little group at the enlargement of the 

 sixth segment. Here we have a radical departure from the first series, no 

 form of which had more than five joints. The honey tubes are long and 

 slender, almost or quite equal to three body segments, and the mouth or tip 

 is a little flared. In the pupa the legs are longer and proportionally more 

 slender than in the wingless ty[)e. 



May 12, the fifth stage was found. There were now a few winged exam- 

 ples and a new series of wingless breeders, the number of stem-mothers hav- 

 ing much decreased, though there were 

 yet many of them present. 



It will be noted that this second series 

 has come to maturity much more rapidly 

 than the first brood, only nine days being 

 required from birth to the i-eproductive 

 stage, instead of fifteen. The number of 

 molts or stages is the same, but each stage 

 is much shorter. 



May 15, there was a marked increase in 

 the number of winged forms, and a new 

 jieriod was entered upon — that of migration 

 or, more properly, flight to other trees. 

 The winged forms require a day to become 

 fully matured, and then most of them, if 

 the day be at all quiet and sunny, fly from 

 the place where they hatched, and, guided 

 largely by the wind, they drift to other 

 trees. So, while tree No. 33 was the only 

 one that previous to this time was lousy, almost all the others in the experi-' 

 ment orchard were now becoming infested by the winged individuals devel- 

 oped on No. 33. While, for convenience, the term " migrant " may be used 

 for the winged form of this species, its true application is to a type which 

 flies to another or alternate food plant. 



The condition of aft'airs found at New Brunswick May 15 existed at 

 Moorestown, Burlington County, at least five days jjreviously. for I received, 

 May 10, some shoots absolutely crowded with winged forms and with what 

 was probably, in part at least, their progeny. So it is likely that in the ex- 

 treme southern counties May 5 will find winged migrants, while north of 

 New Brunswick they will appear a few days later than the fifteenth. 



These winged aphids are about seven-hundredths of an inch in length, 

 but with the wings expanded measure almost or quite twenty-five hun- 

 dredths of an inch. They are green in color, but. the head and the raised 

 portions of the thoracic disc are black. The legs are long and slender, the 



Fig. 1(>— Wingless agamii-, vivipar- 

 ous foniale of second series, ready 

 to reproduce; antennre of this (the 

 longer) and preceding ( the shorter) 

 stages and " tall," yet further en- 

 larged. 



