26 
Psyche 
[February 
that of certain Protorthoptera (Fig. 9), while the branching of 
the radial vein is somewhat suggestive of the condition occurring 
in other Protorthoptera — although the nature of the median 
and radial veins in the Mixotermitoids is much more suggestive 
of the Palaeodictyoptera. The ancestors of the Mixotermitoids 
were possibly intermediate between those of the Hadentomoids 
and those of the Protorthoptera, though the Mixotermitoid 
type apparently harks back to the Palseodictyoptera in many 
respects. 
In the general character of the anals and the cubital veins, and 
more strikingly in the nature of the branching of the median vein, 
the fore wing of the Hapalopteroid insect shown in Fig. 6 ap- 
proaches the Protorthopteron type (Fig. 9) more closely than 
any other, so far as I am aware, and the precursors of the Hapalo- 
teroids are doubtless to be sought among the Protorthoptera 
or their forebears. I formerly adopted Handlirsch’s suggestion 
that the Hapalopteroids were very like the ancestors of the 
Plecoptera; but a closer examination of the venation of the 
Hapalopteroid wings would not bear out this assumption. 
The more primitive types of forewing venation in the Plecop- 
tera, such as that of Eusthenici shown in Fig. 13, apparently 
hark back to a Protoblattid t}^pe resembling in some respects 
the one shown in Fig. 12, in the nature of the cubital and anal veins; 
and the anal fan in the hind wing of Eusthenia is suggestive 
of the anal fan of the Protoblattid hind wing. On the other hand, 
I find much in the venation of the Plecoptera which is suggestive 
of a rather close relationship to the Protorthoptera, and an even 
closer relationship to the Hadentomoids, particularly in the 
nature of the branching of media and radius in the fore wing, 
as may be seen by comparing Fig. 11 with Fig. 10. Furthermore, 
if we compare the fore wing of the Plecopteron shown in Fig. 11 
with the fore wing of the Embiid shown in Fig 8. the branching 
of cubitus, media and radius is strikingly similar, and the evidence 
of the venation is therefore in harmony with that drawn from 
the study of other structures of the body indicating a close rela- 
tionship between the Embiids and the Plecoptera — and if the 
Embiids are to be derived from ancestors resembling the Haden- 
