208 MES0ZOIC INSECTS OF QUEENSLAND, v., 



of this paper. It will follow from this that the primary median 

 fork, like the primary radial and cubital forks, lies close to the 

 base of the wing, and that the more distal fork, which has 

 hitherto been regarded as the median fork, is really the secondary 

 median fork, homologous with the secondary radial and cubital 

 forks. Heyond the formation already described, only one dicho- 

 tomy of Mj_ 4 can be seen in the fossil: but there were almost 

 certainly further dichotomies in the lost portion, judging by the 

 somewhat diverging directions of the branches of M and of R4+5. 

 (M has at least four branches in M. illidgei, apart from the vein 

 M 6 already mentioned). 



Type, Specimen No. 137a. (Coll. Queensland Geological 

 Survey). 



Horizon: Upper Triassic, Ipswich, Q. 



Discussion of the Relationship between the Fossil Prohemerobiidfle 

 and the Recent Psychopsidae. 



In Text-fig. 28, I show the bases of fore- and hindwings of 

 Meyapsychops illidgei (Froggatt), the most archaic of existing 

 Psychopsidte, for comparison with the fossil Archepsychops. It 

 should be stated, at the start, that the venation of Meyapsychops 

 is absolutely unique, and that there is no other known insect, 

 fossil or recent, which possesses the same characters, or anything 

 closely approaching them. From the rest of the Psychojisvhb it 

 is widely separated by the large number and closeness of the 

 branches of lis, the four- to six-branched media, and the remark- 

 able structure of the cubitus. 



Comparing Text-figs. 27-28, we see that the forewing of the 

 fossil ArcJoepsychops is intermediate between the fore- and hind- 

 wings of Meyapsychops in the form of the costal veinlets — the 

 immense breadth of the costal space resembling that of the fore- 

 winy of this latter genus, while the type of branching of the 

 recurrent costal veinlet is that found in the hindwiny only of 

 Meyapsychops. Apart from the absence of the costal series of 

 cross veins, which never occurs in any Prohemerobiid, the prin- 

 cipal difference between the forewings of Archepsychops and 

 Meyapsychojis is the great change in the direction of the costal 



