1922] Uichanco — Notes on Parthenogenetic Macrosiphum 77 



claimed, since the latter membrane arises as a secretion of the 

 egg-periplasm, and has no direct relation to the follicular epithe- 

 lium. 



The extrusion of the nymph from the vagina, from the time 

 the caudal portion of the abdomen of the former begins to pro- 

 trude until the entire bodj- is exposed, takes about five or ten 

 minutes. The insect remains in the condition described above> 

 attached b}' the anterior margin of the head and the bases of the 

 antennae to the external opening of the mother's vagina for 

 about ten or fifteen minutes. At the end of this time, the young 

 insect has dried its skin well enough to set the appendages free 

 from their attachment to the body. A waving motion of the 

 antennae and of the legs then ensue; but the nymph does not 

 seem to struggle to make its final escape. After about five more 

 minutes, the chitinous exoskeleton has probably hardened 

 sufficiently, and the mother then executes two or three sudden 

 peristaltic movements of the abdomen, which set the j'oung 

 nymph free. The newly born aphid usuall}^ remains in close 

 proximity to the place where it is deposited by the mother. In 

 about fifteen or twent}^ minutes after birth the nymph begins 

 feeding, and by this time also the characteristic colors of the 

 body and appendages become evident. 



The position of the mother during parturition is the same as 

 that described in connection with her feeding habits. The 

 abdomen is situated uppermost and the head directed toward 

 the ground. In fact, parturition goes on simultaneously with 

 feeding, apparently without in the least interfering with the 

 latter process. 



Summary of Section V. 1. At birth, the young makes its 

 appearance with the caudal portion of the body first. 



2. After extrusion from the vagina, the nymph remains 

 attached b}^ the anterior margin of its head to the vaginal sHt of 

 the mother until the exoskeleton of the young hardens. The 

 process requires about ten to fifteen minutes, when the nymph 

 finally becomes separated from the mother. 



