26 Psyche [February 



that of certain Protorthoptera (Fig. 9), while the branching of 

 the radial vein is somewhat suggestive of the condition occurring 

 in other Protorthoptera — although the nature of the median 

 and radial veins in the Mixotermitoids is much more suggestive 

 of the Palseodictyoptera. The ancestors of the Mixotermitoids 

 were possibly intermediate between those of the Hadentomoids 

 and those of the Protorthoptera, though the Mixotermitoid 

 type apparently harks back to the Palseodictyoptera in many 

 respects. 



In the general character of the anals and the cubital veins, and 

 more strikingly in the nature of the branching of the median vein, 

 the fore wing of the Hapalopteroid insect shown in Fig. 6 ap- 

 proaches the Protorthopteron type (Fig. 9) more closely than 

 any other, so far as I am aware, and the precursors of the Hapalo- 

 teroids are doubtless to be sought among the Protorthoptera 

 or their forebears. I formerly adopted Handlirsch's suggestion 

 that the Hapalopteroids were very like the ancestors of the 

 Plecoptera; but a closer examination of the venation of the 

 Hapalopteroid wings would not bear out this assumption. 



The more primitive types of forewing venation in the Plecop- 

 tera, such as that of Eusthenia shown in Fig. 13, apparently 

 hark back to a Protoblattid type resembling in some respects 

 the one shown in Fig. 12, in the nature of the cubital and anal veins; 

 and the anal fan in the hind wing of Eusthenia is suggestive 

 of the anal fan of the Protoblattid hind wing. On the other hand, 

 I find much in the venation of the Plecoptera which is suggestive 

 of a rather close relationship to the Protorthoptera, and an even 

 closer relationship to the Hadentomoids, particularly in the 

 nature of the branching of media and radius in the fore wing, 

 as may be seen by comparing Fig. 11 with Fig. 10. Furthermore, 

 if we compare the fore wing of the Plecopteron shown in Fig. U 

 with the fore wing of the Embiid shown in Fig 8, the branching 

 of cubitus, media and radius is strikingly similar, and the evidence 

 of the venation is therefore in harmony with that drawn from 

 the study of other structures of the body indicating a close rela- 

 tionship between the Embiids and the Plecoptera — and if the 

 Embiids are to be derived from ancestors resembling the Haden- 



