No. r3ll] GENESIS OE ORGANIZATION OE INSECT EGG 655 



sary t'oi' the ])ro(liietion of a complete org-anism. In many 

 si^ecies oi* injects and other animals, ])ai't]ienoii-enesis is 

 a normal iiliejiomenoji and in many si)eeies whose eggs 

 nmst ordinarily be fertilized development may be ini- 

 tiated b\ artificial means.-^ Among these are the eggs 

 of llu' silkwdrm moth. Jt also seems certain that the 

 ('> topla-mic legion^ of the in<ect egg have reached a high 

 state (>r morphological and physiological differentiation 

 before fertilization, judging from the results outlined in 

 I*art 1. of this pai)er. 'I'he cleavage nuclei may possibly 

 exeit an inilnence npon the cortical layer of cytoplasm 

 l)ef()r(^ the Ijlastoderm is foi-med, tlierel)y enabling the 

 })ateriial cont rilmtion to the zygote to act, but besides be- 

 iny- v(M'\- improbable, such a iilienomenon would, of course, 

 follow raihei ihan pieeede tile (-t a bl i shmont of the ad- 

 vanced -late of oruMiii/.ation tliat exists in the undevel- 

 ope.l (-g. 



■2. CnH.^fihiho,/ of ihr I*,iniurdhtl (n nu Cdl. 



In r.. lain luetle-. ilie. and para-ili<' 1 ! > menopK ra. tlie 

 primordial uerm eclU are xi^hlN .lilVm-ent from the rest 

 of llie emliryonie cell,- thai arl^' at about the -ame time. 

 T\\\> dilfeicnee is primarily- due to the inclusion within 

 them of viable sul)-tance. that ai'e lo,-ated in the e-o ma- 

 terial from which they originate. The eu2- of tlu-e dif- 

 ferent insects are sinrilar in certain reaped < and dif- 

 ferent in (Others. Tn every inMan.-e. however, thi- visible 

 sul)stan('e, which forms the <i(M'm-liiu> di'terminants, is 

 situated neai- the po-frioi- en.l of the euu. and it i* at this 

 l)oint that the prinioidia; uerm cell- are f<.rmed. The 

 oriu'iii of the iicrm-line (h'tci-minants is not definitely 

 known in any in-ect. luit tli.-ir po-ition in the eu- and 

 their -rainilai- app<'ai-ance are constant. 



It ha- often, he.-n pointed out that the primnrdial o^rm 

 <-ell- remain in a coniparativel> undi ffereni iaicd -tale 

 until the indiNidual in ^^]licl! the^ lie ha- aimo-t reacji^d 

 matni'itv. aini that thcv then nnderu'o cliano-e. during 



