No. 534] INFLUENCE OF CHANGED CONDITIONS 



:-!G7 



this result applies to the pattern as well as to the in- 

 tensity of the coloration. For in the controls qnite as 

 great a range of color variation was found as in the 

 others. Also the unusual conditions of life did not ap- 

 pear to effect the dimensions of the hatched moths. To 

 decide this I took as the most convenient measurement 

 the length of the fore wing, measured from its point of 

 insertion against the thorax to the most anterior edge 

 of a dark spot placed anteriorly near the apex of the 

 wing; I did not measure to the extreme free edge of 

 this wing, for that portion is very flexible and liable to 

 become folded during the process of mounting the moths. 

 The right wing was measured unless it happened to be 

 misshapen. Only about a hundred moths were pre- 

 served, too few for any statistical study of this wing 

 length, consequently in the following table only the ex- 

 tremes of variation of this length are given (expressed 

 in millimeters, and accurate to within a half millimeter). 



Lot 40 (1<J, 5?) control $ length 67.5 $ length 69.0-74.5 



pot 64 (2<f, 6$) control $ length 61.0-65.0 $ length 61.0-75.5 



J Lot 68 (4rf, 3$) <f length 5S.0-64.0 $ length 64.0-73.0 



[Lot 69 (2rf) length 66.0-67.0 



f Lot 79 (3<J, 3$) control $ length 59.5-65.0 $ length 69.0-75.0 



\ Lot SO (Trf, 7$) length 61.5-70.0 $ length 61.0-73.0 



Lot 82 (3rf, 6$) control <? length 67.0-69.0 $ length 66.5-74.0 



Lot 83 (12<J, 6$) $ length 60.0-68.5 $ length 67.0-73.0 



Lot 84 (2^, 4$) length 67.0-67.5 $ length 68.0-71.5 



Lot 85 (12rf, 3?) <J length 63.0-69.0 $ length 65.5-73.0 



It is probable that this late pupal stage is so advanced 

 m its development that it can not become much modified 

 by external changes. 



II. Thyridopteryx ephemeraformis Steph. 

 This psychid is the common " bag-worm" or "basket- 

 worm." The larva immediately on hatching constructs 

 a bag or cocoon of silk covered with portions of leaves 

 or chips, and increases the size of the bag as it grows 

 and carries it about. At the end of the summer each at- 

 taches its bag firmly to the twig of a tree, and the male 



