42 
Psyche 
[March 
Sex determination in the Bethylid, Scleroderma immigrans , 
was formerly thought similar to that of the Apidae where 
unfertilized females produce males. 
The Material. 
My stock of Scleroderma immigrans was obtained in Hawaii 
through the kindness of Dr. Swezey, to whom I am very 
much indebted. 
Having been acquainted with the fact that in Prof. Wheel- 
er’s study of the Texan Scleroderma macrogaster , he was able 
to use quite a variety of food material, I expected to employ 
the larvae of the mediterranean meal moth Hephestia of 
which I had a large stock prepared for Microbracon culture. 
My Sclerodermas refused bark borers and longicorn beetle 
larva and did well only upon larvae and pupae of the pine 
weevil Pissodes strobi. My stock finally perished when the 
latter food became unavailable. 
In the spring of 1928 several vials containing cocoons were 
received from Dr. Swezey. The parents (which we shall call 
Pi generation) were probably born shortly before April 10th, 
when some of the eggs were laid. They consisted of apterous 
females and alate males. 
The results of my breeding experiments are shown in 
Table I. 
