356 Journal of Agricultural Research voi. vi, no. io 



duction was better than in the dry ones, although too much moisture 

 prevented the sexual forms from freeing themselves from the pellicles. 

 Whether the migrants had flown or not did not seem to bear any influ- 

 ence on the deposition of the sexual forms. In most of the dishes more 

 than half of the sexed forms were not extruded, but died unborn. In the 

 rubber cells five-eighths of an inch in diameter and three-sixteenths of 

 an inch in height the migrants did best singly, while the larger stender 

 dishes provided space for a number. In all the dishes pieces of pear or 

 elm bark were provided, but the migrants rarely deposited the sexes on 

 these, nearly always extruding them on the filter paper also provided. 

 It frequently happened that the sexes after having been extruded be- 

 came entangled with the wings or legs of the parents or with each other. 

 The sexes were deposited in rapid succession. The migrants rarely lived 

 beyond three days after they were placed in the dishes, whether they 

 deposited sexual forms or not. None lived longer than six days. 

 They died immediately after the sexes had been extruded and very few 

 deposited their full complement. 



All the sexes deposited were not noted; but about four-fifths of them 

 totaled 109 individuals, of which a little over half (58) were females. 

 Only a few matured, and the majority died unmolted. Undoubtedly 

 the cause of this was the abnormal condition of the environment. How- 

 ever, it appears to be proved that the sexes are produced in about equal 

 numbers, and observations in the field corroborate this. Four fall mi- 

 grants dissected on October 27 and 28 had contained, respectively, 5, 7, 8, 

 and 9 young. In the dishes not more than seven sexes were ever 

 dropped by an individual. The number of males and females depos- 

 ited by individual migrants was found to range from seven females and 

 no males to five males and one female. Probably a larger series would 

 have furnished a migrant producing only males. As a rule the produc- 

 tion of sexes was about evenly divided between male and female. 



The sexes have no woolly covering such as that occurring on the sexes 

 of Eriosoma lanigerum, but are bare and shining. The female, however, 

 at the time of depositing the winter egg, has a patch of short white wool 

 on either side of her body and with this she contrives to clothe partly 

 the winter or impregnated egg. The sexes are active, the male especi- 

 ally so, both immediately after extrusion and following the casting of 

 their fourth and final skin. Between casting their first and fourth 

 skins they remain inactive unless disturbed. Normally they seek crev- 

 ices in the bark, but in the dishes they frequently molted on filter paper 

 or on the sides and floor. 



The sexes mature in from 7 to 1 1 days and molt four times — that is, 

 about every other day. Being beakless, they take no food. 



The males are smaller than the females, the latter being enlarged by 

 reason of the egg within the body. The male at first is light green, with 



