SEXUAL CHARACTERISTICS OF THELIA 58 
allel to the ground and allowing them to drop to the earth. 
These are followed by the remaining individuals which did not 
have a ventral position in the host next to the abdominal 
sterna. . 
The eruciform larvae crawl at a good rate, hunting any small 
opening in the ground. In the laboratory it was found advis- 
able to make small holes in the soft earth in jars into whichthe 
larvae dropped. Finding these holes, they burrow half an inch 
or an inch through the soil and spin a little straw-colored cocoon, 
2.36 mm. in length. The cocoon is almost oval, but a trifle con- 
stricted about the middle where a thickened portion forms a 
little white transverse band. Often the larvae spin their cases 
against stones or the side of the jar furnished the laboratory 
cultures. One could follow the color changes of the enclosed 
larva or pupa, for the cocoon is quite transparent along its sur- 
face of adherence. 
By the end of September, the larva has transformed itself into 
a white-bodied pupa with red or chocolate-colored eyes. The 
abdomen is filled with fat and the intestine is distended with 
crystals and dark unorganized waste material. Evidently the 
winter is passed in this state, the transformation to the jet-black 
adult taking place in the spring. In the laboratory cultures 
kept in a warm greenhouse, development contined. Thus, by 
December the chitinous portions of the Aphelopus were com- 
pletely formed, but the abdominal sclerites were still distended 
with the enclosed fat. In the males sexual maturity was al- 
ready reached, spermatogenesis having been completed; but the 
females contained only minute ova. In April the adults hatched 
in the laboratory; the females then contained fifty to seventy 
full-grown eggs. From these specimens reared in 1916, before 
the adult had been seen in nature, the species was named and 
described by Mr. Gahan. 
Female Aphelopus hunting Thelia nymphs, taken in June, 
1917, were dissected and revealed the fact that in some the 
spermatheca was filled with sperm and in others it was empty. 
Probably fecundated females lay eggs which develop into fe- 
males, whereas virgin females lay eggs which develop partheno- 
