PLATE 13 



Musca domestica : 



A-F. — Various stages in the development of the ovarioles from the time of emergence 

 of the fly until after deposition of eggs. Camera-Iucida drawings from ovarioles 

 stained in carmalum or borax carmine. All drawn on same scale. No, 10 eyepiece 

 and i6-mm. objective. 



G. — Two spermathecae. Caraera-lucida drawing from fresh preparation showing 

 spermatozoa escaping from the severed ends of the ducts and from the splits in the 

 sides of the capsules caused by pressure on the cover glass. 



(170) 



