336 EEV. A. E. EATON ON EECENT EPHEMEEIDiE OE MAYFLIES. 



Figs. 6-17. Euthyplocia, sp. — Nymph-skin. All enlarged. — 6. Dorsal view of the slough of the insect, 

 shed perhaps at the last nymphal moult; scalded and posed in the attitude of Ephemera, PL XXX. 

 7. Underside of head of the same, x 4 diam. 8. Antenna and part of the right mandible, x 7 

 diam. 9. Exterior of labrum, x 20 diam. 10. Right mandible, from beneath, x 17 diam. 

 [The lacinia is doubtless out of shape in this as well as in the other figure.] 11. Corresponding 

 view of part of left mandible, x 17 diam. 12. First maxilla and palpus, x 25 diam. 13. Under- 

 side of labium, 2ud maxillae, and palpi, x 15 diam. 14. Dorsal view of tongue and para- 

 glossse, X 25 diam. 15. Fore leg, X 4 diam. 16. Intermediate leg, and 17. Hind leg, x 4 

 diam. After the figures were drawn, the skin was dried and re-carded (Mus. Roy. de Bruxelles) . 

 Pictet's figures of nymphs of this genus (cited in the text) are inaccurate in several particulars. 



Plate XXX. 



Ephemera vulgata. Nymph. 



Figs. I-I9, all enlarged. — I. Dorsal view of $ insect of advanced grade in an attitude of repose. 

 2. Ventral view of the headless body of another specimen. 3. Side view (partly diagrammatic) 

 of the fore part of the body and head, with legs and antenna cut off, showing the arrangement 

 of the first three abdominal tracheal branchiae, and one of the two conical projections in front 

 of the head in profile, x 7 diam. 4. Underside of head, with antennae cut off, showing the 

 mandibles closed, and the tusks interlocked at their tips, X 7 diam. 5. Anteima, x 15 diam. 

 6. Exterior of labrum, x 25 diam. 7. Right mandible, viewed with the fangs pointing up- 

 wards, X 25 diam. 8. Left mandible, viewed with the fangs in profile, x 25 diam. 9. Part 

 of the right mandible with the fangs in profile, x 25 diam. 10. Exterior of left mandible, 

 X 25 diam. 11. First maxilla and palpus, x 25 diam. 12. Labium and 2nd maxillae, with parts 

 of palpi, viewed from above, x 25 diam. 13. Exterior of the same, with palpi. 14. Dorsum 

 of tongue and paraglossEe, x 25 diam. 15. Fore leg, 16. Intermediate leg, and 17. Hind leg, 

 all X 10 diam. 18. Tracheal branehia of the 1st abdominal pair, x 30 diam. 19. One of 

 the 4th abdominal pair, spread to display the fringes, x 15 diam. (In fluid.) 



Plate XXXI. 



Potamanthus luteus. Nymph. 



Figs. 1-16, all enlarged • — 1. Dorsal view of $ insect of advanced grade, in a posture of repose. 

 2. Veiitral view of the head and body of the same. 3. Side view of the head and part of the 

 prothorax. 4. Underside of head. 5. Antenna, x 25 diam. 6. Exterior of labrum, x 35 

 diam. 7. Right mandible, with tendon attached, x 35 diam. 8. Left mandible, with tendon, 

 x 35 diam. 9. First maxilla and palpus, x 35 diam. 10. Exterior of labium, 2ud maxillse, 

 and palpi, x 35 diam. 11. The same, reversed. 12. Dorsal view of tongue and paraglossae, 

 X 35 diam. 13. Fore leg, 14. Intermediate leg, 15. Hind leg, all x 12 diam. 16. Tracheal 

 branehia of the 3rd abdominal pair. (From Brive, in fluid.) 



Plate XXXII. 



Leptophlebia cinda [fig. 2, L. submarffinata]. Nymph. 



Figs. 1-13, all enlarged. — 1. Dorsal view of insect aboiit i grown, at rest, but with the legs disposed 

 somewhat conventionally. 2. Ventral view of the head and body of a specimen approaching the 

 last moult. 3. Antenna, x 70 diam. 4. Exterior of labrum, x 70 diam. 5. Right mandible, 

 with tendon attached, x 100 diam. 6. Left mandible, with tendon, x 100 diam. 7. First 



