210 
Psyche 
[June 
wings. The fore wing shows a broad subcostal area, unique among 
the Palaeodictyoptera., and very short Sc and Rs, both of which justify 
the establishment of a separate family. On the other hand, the 
branched MA and CuA and the nature of the cross venation are 
very suggestive of the Spilapteridae. In all probability, the Mecynos- 
tomatidae represent a specialized group derived from some spilapterid 
ancestors. 
The structural feature which contributes most to our knowledge 
of the Palaeodictyoptera is the beak, which shows a long lanceolate 
labrum. In this specimen only, so far as known^ the stylets can be 
seen separate from each other at the end of the beak. The outer 
pair of stylets are broad and shorter than the others, the inner pair 
are protruding distally with needle-like tips; at the same time, the 
terminal parts of the outer pair are slightly bent upwards, while the 
inner pair are completely straight. It is possible that this represents 
the beak in its position of actual feeding. Another feature contributed 
by the specimen of dohrni is the detailed structure of the terminal 
segments of the leg, showing five nearly equal tarsomeres and broadly 
spaced claws, with a robust arolium. The following account is dif- 
ferent from that which has appeared in previous discussions of Mecy- 
nostomata , being based upon the observations which I have made 
on the specimen using the techniques already noted. 
The wings were broad and short, almost equal in length and 
width; Sc short, terminating on R; subcostal area very broad in the 
fore wing; branches of Rs and M curving posteriorly in the fore 
wing; MA, MP, CuA, and CuP branched; anal area with several 
veins; anal area somewhat larger in the hind wing; cross veins 
dense, slightly irregular, sometimes anastomosed. 
Body structures: Head very small, with large conspicuous eyes. 
Beak long; labrum elongate; palpi long; clypeus oval. Prothoracic 
lobes with radiating veins and numerous cross veins. Legs relatively 
long; tibiae slightly longer than femur; tarsus five-segmented, with 
claws and arolium. 
Genus Mecy nostomata Metcalf 
Mccynostomata Metcalf, 1952: 230 {pro Mecynostoma Brongniart, 1893 : 
451, nec Mecynostoma Graff, 1882). 
Type species: Mecynostoma dohrni Brongniart (OD). 
Brongniart originally listed five specimens in his description of 
dohrni : 37-8, 37-9, 39-10, 37-11 and 37-12. Handlirsch, in 1919, 
Figure 28. Mccynostomata dohrni (Brongniart) ; specimen 37-8. Holotype. 
