• NUTEITION OF THE OVUM OF SCOLIA DUBIA. 



BY 



WILLIAM A. KEPNER. 



With 2 Plates. 



In SeiDtember, 1906, many larvae of Allorhina nitida were work- 

 ing in the sandy soil and sparse sod of a certain part of the University 

 campus. These larvaj ^\ere being attacked by the very few female 

 Scolia dnbia attended by the more numerous males. Specimens of 

 both the larvae and the wasp were then collected and later sent to Dr. 

 L. O. Howard, Chief of Bureau of Entomology, Washington, D. C, 

 where they were identified by Dr. F. H. Chittenden as ''Scolia dubia 

 and its host the %rub-worm' or white grub, Allorhina nitida, com- 

 monly known as the 'green June beetle' or 'fig eater.' " 



In September, 1907, the larvae of Allorhina nitida were very scarce, 

 but in their place an extensive swarm of Scolia dubia appeared. Of 

 these the females, as they crept over the soil or burrowed into it, were 

 caught and various tissues fixed for future study. The material for 

 this work was all taken from adults. The exoskeleton of the adult is 

 so thick as to make it impossible to section the ovaries in place. The 

 ovaries were, therefore, removed from the body cavity with care and 

 fixed. Certain ovaries were fixed in aceto-sublimate two hours, others 

 in chrom-aceto-formalin one hour, and a third supply in Flemming's 

 stronger fluid five hours. All sectioning was done in paraffin. The 

 sections were made 5, 10 and 15 microns thick and mounted in series. 

 All staining was done on the slide. Borax carmine, iron haema- 

 toxylin, safranin, thionin and methylen green were used in staining. 

 Tissues fixed in chrom-aceto-formalin or in Flemming's stronger 

 fluid and stained with iron haematoxylin gave the best results. 



The ovary of Scolia dubia is a paired structure. Each member 

 of the pair consists of four ovary, tubules which lead into a common 

 oviduct. The histological structure of these tubules is characteristic 



The Journal op Morphology — Vol. XX, No. 1. 



