ERRATA. 
Page 206: For explanation of figs. 5 and 6 substitute— 
Fie. 5.—Forewing of Zelandobius confusus (Hare). 
Fie. 6.— Wings of Zelandobius hudsoni (Hare). 
Page 574: In title, for Natural Self-fertilization read Natural Cross- 
fertilization. 
Page 795, in formula for y, numerator of last term should read су (1—2), 
not Cy(l—z); and in formula for z the denomination should read cy, 
not Cy. 
NOTE. 
A certain number of copies of Volume 53 were issued without Plates 
Nos. 24-27. If any one to whom such a defective volume was supplied wi 
return it to the Secretary a perfect volume will be sent to replace it. 
