1929 ] 
Classification of the Psocidae 
321 
A CLASSIFICATION OF THE PSOCIDAE 
By Nathan Banks 
Museum of Comparative Zoology, 
Cambridge, Mass. 
For a long time it has been customary to divide the Pso- 
cidse into two sections according to the number of joints in 
the tarsi, two or three. By this division certain genera (as 
Myopsocus and Mesopsocus) were placed with the Trimera, 
although their venation is practically the same as the typical 
genus, Psocus , with two-jointed tarsi. The venational pecu- 
liarity of these higher Psocidae is in a certain form of 
stigma, as well as in the modification of the cubital fork to 
form what is called an “areola postica.” The three-jointed 
tarsi is a primitive character, and should not have as much 
weight as a special development within the family. I have 
prepared the following table placing emphasis on this 
areola postica and the stigma. The number of tarsal joints I 
would consider as of not more than tribal value ; hardly, if 
any, more valuable than the forked media in hind wing, 
also a primitive character. 
The use of the number of antennal joints as a primary 
character is open to the same objections as that of the num- 
ber of tarsal joints, with the added force that the groups 
overlap. The use of the character of anal and axillary vein 
in forewing being separate throughout or united at the tip 
transfers the Amphientominae from the other scaly-winged 
species to the group of the true Psocidae. While there is no 
doubt that Amphientomum approximates nearer than does 
any other scaly-winged form, to the true Psocidae, yet the 
venation (except for this condition in the anal region) is so 
close to that of other scaly-winged forms, and so different 
from the true Psocidae that it cannot be neglected with 
reason. Moreover the head of Amphientomum, as well as 
