110 CAUDAL GILLS OF ZYGOPTERID LARV^, 



EXPLANATION OF PLATES I. -VI. 

 Plate i. 



Fig. L — Lateral caudal gill of A nstroJ est es psyche (Selj^s); ( x 11). 



Fig.2. — Median caudal gill of Anstrohsfes cingulafus (Burm.); { x 9). 



Fig. 3. — Pointed tip of same gill of Austrolestes cofensonis (White); ( x 13). 



Fig. 4. — Lateral caudal gill of Synhstes loeyersi Selys; ( x 13). 



Fig. '). — Lateral caudal gill of Synhstes afbicauda Tillyard; ( x 13). 



Fig. 6. — Lateral caudal gill of Xeosticta canescens Tillyard; ( x 11 1. 



Fig. 7. — Median caudal gill of Isosticta simplex Martin; ( x 11). 



Fig. 8. — Lateral caudal gill of A 7'yioleste>i icteromelas Selys; ( x 6). 



Fig. 9. — Median caudal gill of same; i x 6). 



Fig. 10. — Lateral caudal gill of Ar<p'ohstes griseus (jriseus Selys; ( x 13). 



Fig. 1 1 . — Regenerated median caudal gill of same; ( x 131 The basal border 

 of the transverse band of pigment indicates the division between 

 the thicker basal portion of the gill and the thinner distal por- 

 tion. Note the four main trachea?. 



Plate ii. 



Fig. 12. — Median caudal gill of GaUagrion hiUimihursii (Marl in i; ( x 9). 



Fig. 13. — Lateral caudal gill of Psendagrion anstralasite Selys; ( x 11). 



Fig. 14. — Median caudal gill of Anstroagrion cyane (Selys); ( x 13). 



Fig. 15. — Median caudal gill of Ceriagrion ernhescens Selys; ( x 18). 



Fig. 16. — Median caudal gill of Ischimra heterosticta Burm.; ( x 11). 



Fig. 17. — Lateral caiidal gill of Argiocnemis rnbescens Selj^s; ( x 11). 



Fig. 18. — Lateral caudal gill of Austrocnemis sphndida (Martin); ( x 13). 



Fig. 19. — Median caudal gill of same; ( x 13). 



Fig. 20. — Regenerated lateral caudal gill of same; ( x 11). The transverse 

 pigment-band situated one-fourth of the gill-length from the tip 

 indicates the division between the thicker basal portion of the 

 gill and the thinner distal portion. Notice the three main trachea?. 



Plate iii, 



(Transverse sections through the basal portions of the caudal gills.) 



Fig. 21. — T.S. through the breaking- joint of the median gill of Xeosticta 



canescens Tillyard; ( x207). 

 Fig.22. — T.S. through the breaking-joint of the lateral gill of same larva 



(a specimen possessing three main tracheae); ( x 207). 

 Fig. 23. — T.S. through median gill of Calopteryx sp.. close up to base; 



( X 87). 

 Fig.24. — T.S. through left lateral gill and left cercoid (c') of same larva; 



( x 87). 

 Fig.25. — T.S. through the complete gill-s3^stem and cercoids of Synhstes 



weyseri Selys, close up to base; ( x 87), 



I 



