6o 
Psyche 
[June 
The assumption of such a line allows reasonable explanation of 
the evolution of the in-flight wing coupling mechanism, from a set 
of pointed, separated spines in the Trogiomorpha through truncated 
spines set close together in the Amphientomidae, to a hook composed 
of truncated spines fused at their bases in the Psocomorpha. If the 
electrentomoid families are placed along the line leading to the 
Amphientomid-Psocomorph group as in the dendrogram (fig. 104) 
more steps are added to the in-flight wing coupling mechanism series 
(figs. 92 through 97). The absence of this structure in Nanopsocetae 
is probably secondary. The lacinial tips and ovipositor valvulae also 
form rational series along this line. 
It appears, therefore, that the Psocomorpha are phylogenetically in- 
cluded within the Amphientometae as a terminal monophyletic group. 
1 here are, however, some characters which suggest a contrary con- 
clusion. For example, the rasp of the coxal organ is found in the 
Psocomorpha and Trogiomorpha but not in the Amphientometae or 
Nanopsocetae. This would be regarded as a new apomorphous 
development of the Psocomorpha in the theory developed above. 
The relationship of the Nanopsocetae to the Trogiomorpha and the 
line bearing the Amphientometae and Psocomorpha still needs to be 
investigated. The Nanopsocetae and Amphientometae have been 
placed close together on the basis, in part, of plesiomorphous char- 
acters. However, it appears that the T-shaped sclerite of the 
subgenital plate, the tympanum of the posterior coxa, and ringing 
sculpture patterns of the antennal flagella, all characters absent in 
the Trogiomorpha and apparently absent in closely related orders, 
are here apomorphous and mark out a Nanopsocetae-Amphientometae 
line. 
The electrentomoid families, then, bridge the gap between the 
Nanopsocetae and Amphientomidae. This accounts for why we find 
within this series of families forms very similar to the Nanopsocetae 
( Musapsocus, with lacinial tip of three tines and third valvula 
simple) and other forms very similar to the Amphientomidae 
( Compsocus, with lateral cusp of lacinial tip curved and bearing 
short, rounded denticles, third valvula deeply bilobed, compound eyes 
transversely color-banded). They arise precisely between the point 
on the line leading to Amphientomidae and Psocomorpha where the 
nodulus is acquired and the point where ctenidiobothria are acquired. 
It must be noted that most of the species of the electrentomoid 
complex commonly share one apomorphous character: the junction 
of veins iA and 2 A in the forewing. This character is not universal, 
however, being absent in Musapsocus huastecanus and in Manicapso- 
