151 

 Smitli and Pritchard: Odonota 



■EC* 





Fig. 4:91. Coloration of / schnuro. a, gemina; b, denticollis; 

 1, lateral view of male; 2, dorsal view of posterior end of female 

 abdomen; 3, lateral view of female (Kennedy, 1917). 



— Prothorax without dorsal projections 4 



', 3. Abdomen with dorsum of segment 10 entirely black 



(figs. 4:88<i; 4:9262) denticollis 



— Abdomen with blue spots on dorsum of segment 10 

 (figs. 4:89; 4:92a2) gemina 



4. Prothorax with dorsoposterior margin evenly convex 



5 



— • Prothorax with small, dorsomedian emargination on 

 caudal margin (fig. 4:88e) demorsa 



5. Abdominal segment 8 with a well-developed medio- 

 ventral spine (fig. 4:88a) barberi 



— Abdominal segment 8 without a medioventral spine or 

 with this spine rudimentary 6 



6. Abdomen more than 21 mm. long 7 



— Abdomen less than 20 mm. long (figs. . 4:88c; 4:91) 



perparva 



7. Hind wing more than 19 mm. long (fig. 4:88/) 



ramburii credula 



' — Hind wing less than 14 mm. long erratica 



Naiads 13 



1. Dorsal setigerous margin of the median gill extending 

 more than 1/2 length of gill; mental setae 3-4, some- 

 times a vestigal fifth; lateral setae 5 perparva 



— Dorsal setigerous margin of median gill extending 1/2 

 length of gill or less 2 



2. Dorsal setigerous margin extending 1/2 length of gill; 

 marginal setae of median lobe 4-5; lateral setae 6; 

 femora with preapical rings of brown 



ramburii credula 



Dorsal setigerous margin not extending beyond 1/3 

 length of gill 3 



3. Body length, not including gills, 15 mm barberi 



■ Body length, not including gills, 12 mm. or less .... 



cervula and denticollis 



REFERENCES 



AHRENS, C. 



1938. A list of dragonflies taken during the summer of 

 1936 in western United States (Odonata). Ent. News, 

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 BICK, GEORGE H. 



1941. Life-history of the dragonfly, Erythemis simpli- 



collis (Say). Ann. Ent. Soc. Amer., 34:215-230. 

 1953. The nymph of Miathyria marcella (Selys). Proc. 

 Ent. Soc. Wash., 55:30-36. 

 BORROR, D. J. 



1934. Ecological studies of Argia moesta Hagen (Odonata: 



Naiads of gemina, demorsa, and erratica are undescribed. 



ICO 



Fig. 4 : 92. /schnura naiads. a,b, cervula; c, perparva 

 (Kennedy, 1915). 



Coenagrionidae) by means of marking. Ohio Jour. Sci., 



34:97-108. 

 1942. A revision of the libelluline genus Erythrodiplax. 



Ohio State Univ. Grad. Sch. Stud., Biol. Series, Contrib. 



Zool. Ent., 4:XV 1-286. 

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Ann. Ent. Soc. Amer., 38:168-194. 

 BYERS, C. F. 



1927a. Key to the North American species of Enallagma, 



with a description of a new species (Odonata: Zygop- 



tera). Trans. Amer. Ent. Soc, 53:249-260. 

 19276. Enallagma and Telagrion from Western Florida, 



with a description of a new species. Ann. Ent. Soc. 



Amer., 20:385-392. 

 1927c. Notes on some American dragonfly nymphs 



(Odonata, Anisoptera). Jour. N.Y. Ent. Soc, 35:65-74. 

 1927a". The nymph of Libellula incesta and a key for the 



separation of the known nymphs of the genus Libellula. 



Ent. News, 38:113-115. 

 1930. A contribution to the knowledge of Florida Odonata. 



Univ. Florida Publ. Biol. Sci. Series, 1:1-327. 



1936. The immature form of Brachymesia gravida, with 

 notes on the taxonomy of the group (Libellulidae). 

 Ent. News, 47:35-37. 



1937. A review of the dragonflies of the genera Neuro- 

 cordulia and Platycordulia. Univ. Mich. Misc. Publ., 

 36, 36 pp. 



1939. A study of the dragonflies of the genus Progomphus 

 (Gornphoides) with a description of a new species. 

 Proc Fla. Acad. Sci., 4:19-86. 

 CALVERT, P. P. 



1901-1908. Biologia Centrali-Americana. Insecta. Odon- 

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1928. Report on Odonata, including notes on some 

 internal organs of the larvae collected by the Barbados- 

 Antigua Expedition from the University of Iowa in 

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1934. The rates of growth, larval development and 



