EEV. A. E. EATON ON RECENT EPHEMERID.E OE MAYFLIES. 339 



12. Upperside of labium and 2iid maxillfe, x 40 diam. 13. Doi'sal view o£ tongue and 

 paraglossse, x 40 diam. 14—16. Legs numbered in succession, x 13 diam. 17-22. Tracbeal 

 branchiae of the riglit side of the abdomeu, one of every pair, together with a second figure of 

 the third of them; figures 17, 18, and 20-22 represent the complete series numbered consecu- 

 tively from the foremost ; figure 19 is the reverse of the tliird in the series. (In alcohol.) 



Plate XL. 



Figs. 1-17. Nymph No. IV., allied to Ephemerella, described at p. 133. Figures aU enlarged. — 

 1. Dorsal view of a nymph-skin out of which the subimago had emerged. 2. Ventral view of 

 head and body of the same. 3. Vertical view of head, x 10 diam. 4. Exterior of labrum, 

 X 25 diam. 5 and 6. Right and left mandibles, x 40 diam. 7. First maxilla and palpus, 

 X 40 diam. 8. Underside of labium, 2nd maxilhe, and palpi, x 40 diam. 9. Dorsal view of 

 tongue and paraglossse, x 40 diam. 10-12. Legs, numbered successively from the foremost, 

 X 12 diam. 13-lG. Tracheal branchiffi of the abdomen, one of every pair, numbered consecu- 

 tively from the foremost, x 25 diam. 17. The third of them reversed, x 25 diam. (In 

 alcohol.) 

 Figs. 18-20. Nymph No. V., allied to Ephemerella, described at p. 133 [Supplemented by PI. LXIV. 

 figs. 3-8]. Figures all enlarged. — 18. Dorsal view of insect of advanced grade. 19. Ventral 

 view of head and body of the same. 20. Tracheal brauchia of the 3rd abdominal pair, 

 reversed. (In alcohol.) 



Plate XLI. 



Reputed Nymph of Tricorythus. 

 Pigs. 1-20, all enlarged. — 1. Dorsal view of insect of very advanced grade. 2. Ventral view of head 

 and body of the same. 3. Antenna, x 35 diam. 4. Exterior of labrum, x 35 diam. 

 5. Right mandible with tendon attached, x 65 diam. 6. Left ditto, x 65 diam. 7. First 

 maxilla and palpus, x 65 diam. 8. Tongue and paraglossse, x 35 diam. 9-11. Legs 

 numbered consecutively from the foremost, x 20 diam. 12. Foremost right abdominal 

 tracheal branchia [after Vayssi^re]. 13-17. Left tracheal branchiae of the remaining pairs 

 numbered consecutively, x 30 diam. 18. Left tracheal branchia of the 2nd abdominal pair 

 reversed, showing the marginal flange along the inner border, x 30 diam. 19. Part of the 

 exterior of the right tracheal branchia of the same pair, showing the row of hairs along the 

 inner border which hitch under the flange of the opposite one, x 30 diam. 20. Outer and 

 part of the median caudal setaj, x 15 diam. 21. Underside of labium, 2nd maxillae, and 

 palpi, X 65 diam. (In alcohol, from Dr. E. Joly ; captured at Toulouse.) 



Plate XLII. 



Canis halterata, figs. 1, 2, 7-17, and 22-25 ; a species from Portugal figs. 3, 4; and C luctuosa, 

 — Harrisella, figs. 5, G, 18-21, and 27-28. Nymphs. Figures all enlarged. — 1. Dorsal 

 view of insect of advanced grade, at rest, but with the intermediate legs disposed somewhat 

 conventionally. 2. Vertical view of head, showing the large rounded hinder ocelli prominent 

 above the oculi, x 30 diam. 3. Dorsal view of insect of very advanced grade, and of another 

 species, remarkable for the dilated lateral borders of the notum. 4. Ventral view of head and 

 body of the same. 5. Vertical view of head of C. Harrisella, remarkable for the conical 

 tubercles upon the sites of the ocelli, x 20 diam. 6. Antenna, x 50 diam. 7. Exterior of 

 labrum, x 65 diam. 8. Right mandible with tendon, x 100 diam. 9. Left ditto. 10. Part 

 of right mandible of another specimen placed to disjflay the fangs, x 50 diam. 11. The same 



