EPHEMERIDA, ODONATA, PLECOPTERA, ET AL. 



201 



instar. The yolk globules disappear early in the second day. The 



vacuolated compartments (spherules) 

 linger on for five days in Erythemis and 

 even longer in Plathemis. 



It is evident that Tschuproff's 



figure represents only an intermediate 



stage in the growth of the definitive 



digestive epithelium corresponding 



stom^— — ^^f ^^^!f®^ roughly to Fig. 126 of Plathemis. 



PLECOPTERA 



The Stone Fly (Pteronarcys proteus 

 Newman) 



^ ^ Miller (1939), in his work on the 



r ~^^ embryology of the stone fly, states 

 't^ii that adults reared from nymphs mate 



proci 



Ftg. 125. — Plathemis. Longitud- 

 inal section of mid-gut at time of 

 hatching, (lu) Lumen, (stom) Stomo- 

 daeum. {proct) Proctodaeum. 



Fig. 126. — Plathemis. Longi- 

 tudinal section of mid-gut several 

 hours after hatching, iy.sp) Yolk 

 spherule. 



readily in captivity. A single female, during a lifetime of three weeks or 

 less, produces a total of 500 to 1,000 eggs in batches of as many as 450 



