90 
Psyche 
[June-Sept. 
operates the parts in the basal region of the aedeagus, and 
the hypandrial apodeme, ha, of Figs. 19 and 21, which is 
formed by an internal inflexion of the ninth sternite or 
hypandrium, 9s, for the attachment of muscles moving these 
structures. Lowne, 1895, designates the structures labelled 
pg in Fig. 19, as the paragonia (they have been called 
seminal vesicles by other writers) and states that the secre- 
tions of these structures coagulates in the ejaculatory duct, 
or in the vagina of the female, to form a type of spermato- 
phore. The seminal fluid is ejaculated through the action 
of the ejaculator em of Fig. 19, which functions as a syringe 
to force the fluid out through the aedeagus when the muscles 
attached to the sclerite in its membranous walls, etc. 
contract. 
The interpretations given the different structures here 
discussed are the same as those proposed six years ago in a 
short paper published in the Bulletin of the Brooklyn Ento- 
mological Society for 1936, Vol. 33, No. 4, p. 141. This 
earlier paper, however, was apparently too brief and the 
accompanying figures were too few, to carry any conviction 
for those who have published on the morphology of the 
Mecoptera, Diptera, etc., since that time, so that no consid- 
eration has been given by recent investigators to the views 
set forth in this previous paper. It is to be hoped, however, 
that a re-statement of these views, illustrated by a wide 
series of intermediate forms indicating the steps in the 
development of the structures of the higher Diptera, will 
cause other investigators to take these views into considera- 
tion, since the conclusions here drawn are based upon an 
extensive study of a wide range of Dipterous types, and the 
clear cut evolutionary trends here described must be ex- 
plained in some other way if the interpretations here sug- 
gested are not accepted. 
