30 
Psyche 
[February 
far as I am aware, occurs exactly in that fashion only in the 
Homoptera and Psocids, the nature of the thoracic terga and 
wing bases, the nature of the tarsal segmentation, and other 
regions of the leg, the nature of the abdominal segments in 
general, the segments of certain males and the ovipositors of 
certain females in particular, and many other features too 
numerous to mention at this point, all clearly indicate so close a 
relationship between the Psocids and Homoptera, that it would 
be stretching the laws of probability and chance far beyond the 
breaking point to claim that the marked similarity in all of these 
structures from all parts of the body, and extending through a 
wide-ranging series of forms, is merey the result of “conver- 
gence,” and it would be very interesting to learn from those who 
continually cry “convergence” whenever similarities are pointed 
out between the Psocids and Homoptera, just how “convergence” 
could be brought about in so wide a range of forms and in such a 
multitude of details from all parts of the body! That the many 
similarities in structures from other parts of the body extend 
to the venation of the wings as well, in the Psocids and Homop- 
tera, is shown in the series of insects figured in Figs. 17 to 24, which 
includes some of the most primitive, and the most highly special- 
ized, as well as the intermediate types of venation, in the two 
groups of insects. Thus, the peculiar “broken” character of the 
venation of the apical portion of the Psocid wing shown in Fig. 24 
is paralleled by the wing of the Homopteron shown in Fig. 23, al- 
though the fore wing of the Plomopteron Cercopis sp., figured by 
Handlirsch, 1909, would have been better for a comparison with the 
Psocid shown in Fig. 24, than is the case with the Homopteron 
shown in Fig. 23. The broader more primitively veined Psocid wing 
shown in Fig. 22 is paralleled by that of the Homopteron shown 
in Fig. 21, and the venation in the two is quite similar. Turning 
next to the intermediate type of venation shown in Fig. 18, 
it is quite evident that the Psocid* shown in Fig. 18 is approached 
by the Homopteron shown in Fig. 20, especially in the char- 
acter of the anals, and the branching of cubitus and media, 
which is strikingly similar in the two groups of insects, and there 
is evidently a tendency toward the formation of a pterostigma 
