'28 
Psyche 
[February 
Psocids such as Embidopsocus, for example, suggests a very close 
relationship between the Psocids and Embiids, and since the 
Psocids were apparently derived from Protorthoptera-like 
ancestors (as will be presently discussed) it is to be expected 
that their near relatives, the Embiids, would also be derived from 
Protorthoptera-like ancestors, so that in indicating an ancestry 
for the Embiids anatomically intermediate between the Haden- 
tomoids and Protorthoptera, the evidence of the wing venation 
is quite in harmony with that from other sources as well. 
The venation of the Psocid wing shown in Fig. 1 is so similar 
to that of the Zorapteron shown in Fig. 3, that both were evident- 
ly derived from the same source, and what applies to one applies 
to the other as well. The Psocid and Zorapteron wings shown 
in Figs. 3 and 1 could readily be derived from the Embiid type 
of fore wing shown in Fig 7 (as is indicated in the hypothetical 
intermediate condition shown in Fig. 5)* in the following way. 
The second branch of cubitus of Fig. 7 might become more verti- 
cal, while vein M, which arises from M + Cu and coalesces for a 
short distance with Rs. in Fig. 7, might unite with Rs further 
from the base of the wing thus lengthening that portion of M 
which extends between M + Cu and Rs, as in Fig. 3. R2 + 3 of 
the radial sector, Rs, bends upward toward Ri in Fig. 7, and if 
R4 + 5 were to unite with it to form a single branched Rs bending 
forward to meet Ri, the condition exhibited by Rs in Fig. 3 
would be produced. A deposition of chitin and pigment in the 
space between Sc and Ri (as indicated in Fig. 5) would produce 
a pterostigma such as the one labeled “ps” in Figs. 1 and 3. 
Judging from the same developmental tendencies found in the 
Psocids, Zoraptera, and Embiids, it would appear that all three 
were derived from a common ancestral source, and many of the 
genes, determinants, or factors occurring in this common source 
were inherited by the three derived groups, although they were 
naturally slightly modified by other factors in the derived 
groups, as would be expected. As is pointed out in the next 
paragraph, the ancestors of the Psocids were apparently very 
similar to the Protorthoptera, and since the Psocids, Zoraptera 
*The figure in the left hand column between Figs. 3 and 7 is Fig 5. The label was lost 
“from this figure, having been pasted on too insecurely. 
