io8 



GEORGE O. SHIN'JI. 



sented farther on, but I shall now attack the problem by experi- 

 mental means. 



The weight of a number of fresh rose twigs, similar to those 

 used in my other experiments, was recorded. One of these twigs 

 was then planted in a tumbler containing distilled water, and one 

 in a tumbler containing calcium chloride, in the manner already 

 described. Three days later, the twigs were taken out of the 

 tumblers, placed on a paper, and left to dry from four to twenty- 

 four hours. The second or dried weight of each was recorded, 

 and the twigs then replaced in their respective tumblers. Three 

 to four apterous viviparous females were then transferred to each 

 of them, and a careful watch kept for the young. The fol- 

 lowing tabulation shows the results obtained: 



TABLE V. 



THE EFFECTS FROM THE WILTING OF THE PLANT. 



Thus the mere wilting of the plant is not a factor in the pro- 

 duction of the winged aphids. The drying out of the plant may, 

 however, indirectly help to produce the winged insects by con- 

 centrating the ingredients in the plant tissues. 



VII. MORPHOLOGICAL STUDY. 



The young female aphids are, externally at least, well developed 

 at the time of their birth. They have three pairs of legs and a 

 pair of antennae as stout as their mother's, but shorter. A 

 pair of so-called honey-tubes and the caudal appendage are also 



