55 



been observed to arise farther mesad from the outer series than the 

 width of their bases. 



The length of the pupa of A. packardi varies from .748 to 

 .88 mm., the greatest width from .407 to .54 mm. 



Adult. The following formula shows about the average propor- 

 tionate lengths of the segments of the antennae in the female : 2 — 

 5 — io| — 3 — 4 — 3^ — 3^. The segments of the antennae of the males 

 are slightly smaller, but show about the same proportion. 



The two basal segments seem to be of little systematic import- 

 ance, as they can rarely be accurately measured owing to the fact 

 that in specimens mounted in balsam their long axis is seldom perpen- 

 dicular to the line of vision. I have therefore considered 2 — 5 their 

 proportionate length in both species, these numbers being approxi- 

 mately correct. In A. packardi the following formula indicates the 

 range of variation in length observed in each segment, omitting the 

 two basal ones: (10-12)— 3— ( 4 - 4 |)— (3-4)— (3-5). 



For convenience of comparison the following formula, repre- 

 senting the range of variation observed in the same segments of A. 

 vaporariortim, is again given : (9-1 1) — 4 — (5-6) — (4-5) — (4-5)- 



The length of the fore wing of A. packardi is about 1.16 mm., 

 the breadth about .48 mm. 



The length of the body of the adult female varies from 1.15 to 

 1.20 mm. ; average length of the male about .90 mm. 



NOTES ON LIFE HISTORY AND INFLUENCE OF 



WEATHER. 



This species evidently passes the winter entirely in the egg 

 stage. Here in Amherst the adults become extremely abundant 

 every fall, and hundreds, or even thousands, of eggs are deposited on 

 nearly every leaf. The adults are very hardy, and egg laying may 

 continue up to the middle of November, the larvae and pupae having 

 all been killed by the frosts some weeks earlier. 



In the spring a few consecutive warm days in March cause 

 many of the eggs to hatch. The young larvae, however, being in the 

 most delicate stage, will, as a rule, succumb to the frosts up to the 

 first of April, or even later. In the spring of 1902 all the eggs had 

 hatched by the end of the first week in May. The first adults 

 emerged about the middle of May, and from this time until Novem- 



