1922] Crampton — Relationship of H emiptera-H omoptera 
29' 
and Embiids apparenty sprang from the same source, it is very 
probable that their common ancestors were very like the Pro- 
torthoptera in many respects. 
That the fore wing of a Psocid could be readily derived from a 
Protorthopteron prototype may be seen by comparing the fore 
wing of the Psocid shown in Fig. 2 with that of the Protorthop- 
teron shown in Fig. 4, since the venation of the two wings is 
strikingly similar, and the Protorthopteron type is evidently 
the more primitive one, since it is one of an older and lower 
group, and the branching of the veins in general begins nearer 
the base of the wing — which is usually a more primitive character 
than for the branches to come off nearer the apex, since the latter 
usually indicates a degree of coalescence, and hence a special- 
ization, in the veins. The three anal veins are much alike in 
Figs. 2 and 4, and the forking of the cubitus in the Protor- 
thopteron shown in Fig. 4 (or better still in the Protorthopteron 
shown in Fig. 26) is strikingly like that of the Psocid shown in 
Fig. 2. The three branches of media, and the two branches of 
Rs are also strikingly similar in the insects shown in Figs. 4 and 2, 
and the nature of the first branch of radius and the subcostal 
vein is much the same in both. The Psocids and Protorthoptera 
thus apparently have many developmental tendencies in com- 
mon, and probably inherited them from a common ancestry 
which was very like certain Protorthoptera in may respects, 
and as was mentioned above, the ancestors of the Zoraptera and 
Embiids probabty also resembled the Protorthoptera in many 
respects. As will be shown in the next paragrpah, the Psocids 
and Hemiptera-Homoptera have so much in common, that they 
also in all probability were derived from the same type of an- 
cestors which must likewise have resembled the Protorthoptera 
in many respects, although the ancestors of the Homoptera in 
all probability resembled the Protoblattids as well, and the 
“roots” of the Idomopteron stem apparently strike somewhat 
more deeply down into the Palseodictyopterous types. 
The peculiar bulging antefrontal region of the head incorrectly 
called the “clypeus” in Cicadicl Homoptera and Psocids, the 
peculiar lengthening of the segments of the antennae, which, so* 
