CHAPTER XVI 



OLIGONEPHRIDIA 



COPEOGNATHA, ANOPLURA, THYSANOPTERA, HEMIPTERA 

 COPEOGNATHA 



A Viviparous Psocid (Archipsocus fernandi) 

 This psocid, which is found among dry leaves in Ceylon, has been 

 studied by Fernando (1934) with respect to its development. The 

 abdomen of a gravid female may contain more than a dozen embryos in all 

 stages of development, which remain in the ovarian tubules and finally 

 pass down the common oviduct to the exterior. The mature ovum, which 



f^- 







0.3 



WS^CiX>")■■^^ 



ent.a 



Fig. 167. — Archipsocus. Ovuminovar- Fig. 168. — Archipsocus. Sagittal sec- 



iole {ovt). ipr) Periplasm, {trc) Tropho- tion. (bid) Dorsal blastoderm, (ent) An- 

 cyte. iy) Yolk. terior (a) and posterior (p) entoderm 



rudiments, (gb) Germ band, (gc) Germ 

 cells, {trc) Trophocyte. 



measures 57.6 microns in length, has neither yolk nor chorion and entirely 

 fills the ovarian tubule in which it lies. As the egg travels down the 

 ovarian tubule, cleavage begins. The first division results in the produc- 

 tion of two nuclei, which come to He in the center of the egg, embedded in 

 the central cytoplasm. When about six nuclei (blastomeres) are pro- 

 duced, they are found embedded in the periplasm (Fig. 167), with two 

 nuclei surrounded by cytoplasm, remaining in the center and giving rise 

 to the vitellophags (trc trophocytes) . The egg now elongates, the periph- 



248 



