34.4 EEV. A. E. EATON ON EECENT EPHEMERID.^ OR MAYFLIES. 



Plate LVII. 

 Nymph No. I., allied to Ecdyurus, described at p. 262. 



Figs. 1-21, all enlarged. — 1. Dorsal view of insect of very advanced grade. 2. Ventral view of head 

 and body of the same. 3. Face, x 12 diam. 4. Part of antenna, x 40 diam. 5. Labrum, 

 X 35 diam. 6. Right mandible, x GO diam. 7. Left ditto. 8. First maxilla and palpus, x 

 40 diam. 9. Underside or exterior of labium, 2nd maxillae, and palpi, x 20 diam. 10. Dorsal 

 view of tongue and paraglossae, x 35 diam. 11-13. Right legs, numbered successively from 

 the foremost. 14-20. Tracheal branchiae of the abdomen, one of every pair, numbered 

 consecutively from the foremost, the 2nd reversed to display the arrangements of the fibrils, 

 X 35 diam. 21. Median and part of the left caudal sette, x 12 diam. (In alcohol.) 



Plate LVIII. 



Nymph No. II., allied to Ecdyurus, described at p. 263. 



Figs. 1-21, all enlarged. — 1. Dorsal view of insect of advanced grade. 2. Ventral view of head and 

 body of the same. 3. Face, x 12 diam. 4. Antenna, x 40 diam. 5. Interior surface of 

 labrum, x 20 diam. 6. Part of the right mandible, x 35 diam. 7. Left mandible, x 35 diam. 

 8. Fii'st maxilla and palpus, x 35 diam. 9. Underside of labium, 2nd maxilhe, and palpi, 

 X 15 diam. 10. Dorsal \'iew of tongue and paraglossae, x 15 diam. 11. Right fore leg, 

 X 20 diam. 12 & 13. Left legs of the other pairs, numbered successively, x 20 diam. 

 14-20. Tracheal branchiae of the abdomen, one of every pair, numbered consecutively from 

 in front, x 30 diam. 21. The 3rd of them reversed to display the explanate webbed fibrils, 

 X 40 diam. (In alcohol.) 



Plate LIX. 



Nymph No. III., allied to Ecdyurus, described at p. 264. 

 Figs. 1-19, all enlarged. — 1. Dorsal view of ? insect of very advanced grade, lacking setae. 2. Ventral 

 view of head and body of the same. 3. Part of antenna, x 50 diam. 4. Inner side of labrum, 

 X 50 diam. 5. Right mandible, x 70 diam. 6. Left ditto. 7. First maxilla and palpus, 

 X 70 diam. 8. Underside or exterior of labium, 2nd maxillae, and palpi, x 25 diam. 9. Dorsal 

 view of tongue and paraglossia, x 50 diam. 10-12. Right legs of every pair, numbered 

 successively from the foremost. 13-19. Tracheal branchiae of the abdomen, one of every 

 pair, numbered consecutively from in front, x 50 diam. (In alcohol.) 



Plate LX. 



Heptagenia [ccerulans] gaUica. Nymph. 

 Figs. 1-23, all enlarged. — 1. Dorsal view of ? insect of very advanced grade, at rest. 2. Ventral 

 view of thorax and abdomen of another ? specimen. 3. Face. 4. Underside of head. 

 5. Antenna, x 35 diam. 6. Exterior of labrum, x 25 diam. 7. Right mandible, x 40 diam. 

 8. Left ditto. 9. First maxilla and palpus, x 40 diam. 10. Underside of labium, 2nd 

 maxillae, and palpi, x 25 diam. 11. Dorsal view of tongue and paraglossae, x 30 diam. 

 12. Left fore leg, x 12 diam. 13 & 14. Right legs of the other pairs, numbered successively 

 from the foremost, x 12 diam. 15-21. Tracheal branchiae of the abdomen, one of every pair, 

 numbered consecutively from in front, x 30 diam. 22. The 1st of them reversed, to display 

 the fibrils x 30 diam. 23. Right and median caudal setae, x 12 diam. (In alcohol, from 

 Toulouse.) 



