10 Psyche [February 
a “*Plecopteroid”’ ancestry for the Coleoptera and Dermaptera. 
The segments of the leg are very similar in Embiids, Plecoptera 
and Dermaptera, and the relationship of the Dermaptera to the 
Plecoptera is likewise shown by a comparison of the thoracic 
sclerites (or of the head region) of a nymph of the Plecopteron 
Perla with those of the Dermapteron Arizxenia, the resemblance 
being very striking, as has been shown in a paper dealing with the 
thoracic sclerites of immature Pterygotan insects, which will soon 
be published. The tendency toward the shortening and thickening 
of the fore wings is quite marked in certain Plecoptera, and the 
pleural thoracic sclerites of the Embiids are in many respects very 
like those of the Dermaptera. In this connection, I wouid call 
attention to the fact that in the Embiids (Fig. 3) the nature of the 
postscutellar region of the metathorax and the first abdominal 
segment, with the bulging lateral regions, is very suggestive of the 
condition found in the Strepsiptera; but, since Dr. Pierce is mak- 
ing a comparison of the thoracic region of the Strepsiptera with 
other insects, which he finds more similar to the Strepsiptera than 
the Embids are, the affinities of the Strepsiptera can be more 
accurately determined when the results of his extended studies 
are published. : 
Although the study of the terga and wing bases points to a close 
relationship between the Dermaptera and Coleoptera, and between 
the Embiids and Plecoptera, the evidence afforded by these struc- 
tures alone is insufficient to establish the affinities of the insects in 
question. On this account, a comparative study of the structures 
least subject to modification, and those situated in widely sepa- 
rated parts of the body, has been undertaken in order to demon- 
strate the relationships here proposed. Such an extensive treat- 
ment of the subject, however, requires more space and plates than 
can be afforded a single article; so that the summing up of the 
arguments for the relationships here proposed, can be more con- 
vincingly set forth after the evidence from the more extensive 
study of the parts has been presented in the proposed series of 
articles dealing with this subject. 
BrsLioGRA PHY. 
1914,. Crampton—Notes on the Thoracic Sclerites of Winged 
Insects. Ent. News, 25, p. 15—(Sclerites of Dermaptera 
and Plecoptera figured). 
