8 
Psyche 
[March 
different orders of insects, and the homologies of the parts 
in Diptera, Mecoptera, etc., are still in dispute. 
In a discussion of the male genitalia of Diptera, Mecop- 
tera, and related forms, published in Vol. 25, p. 47, of 
Psyche for 1918, the structures labelled st and cx in figs. 
3, 7, 8, etc., were designated as the gonopods; but in at- 
tempting to homologize the gonopods of sawfiies (which 
are fundamentally like those of Diptera and Mecoptera, 
but are of a more primitive type) with the gonopods of 
male Ephemerids, etc., which have retained the parts in 
practically the original condition for insects in general (see 
Canadian Entomologist, Vol. 52, p. 178, for 1920), I was 
misled by the fact that the bilobed basal plate (called the 
“cardo” by Hymenopterists) of some sawfiies’ genitalia re- 
sembles the fused coxites in the male genitalia of certain 
mayflies and the two-segmented forceps of these sawfiies 
resemble the styli of certain mayflies, in which the styli 
are composed of two or more segments. Using the condi- 
tion exhibited by these sawfiies as the basis for determining 
the homologies of the parts in Diptera and Mecoptera, I 
consequently homologized the segment labelled st in figs. 
3 and 7, of the Diptera and Mecoptera with the distal seg- 
ment of the stylus (i. e., with the dististyle) and homolo- 
gized the basal segment labelled cx with the basal segment 
of the stylus (i. e., with the basistyle), and interpreted the 
demarked basal areas of these basistyles as the reduced 
coxites in Diptera and Mecoptera (see also Vol. 48, p. 207, 
of the Transactions of the American Ent. Soc. for 1923). 
In his review of Dr. Alexander’s “Craneflies of New York,” 
however, Walker, 1920 (Canadian Entomologist, Vol. 52, p. 
190), states that in the Diptera the distal portion of the 
claspers (i. e., st of fig. 3, represents the entire stylus, 
while the basal portion cx of fig. 3 represents the coxite 
instead of the basal segment of the stylus, and Eyer, 1924, 
(Annals Ent. Soc. of America, Vol. 17, p. 275) applies this 
interpretation to the Mecoptera and other Holometabola. 
Mr. R. E. Snodgrass, who has been making a detailed study 
of the musculature of the genital claspers, etc., of male in- 
sects, informs me that the musculature bears out the view 
that the basal segment of the gonopods (labelled cx in the 
