121 



Smith and Pritchard: Odonato 



7. Caudolateral margin of head from dorsal view with 2 

 large, well-developed tubercles (fig. 4:100; eyes small, 

 occupying only one-third of the lateral margin of the 

 head 8 



- Caudolateral margin of head from dorsal view never with 

 2 tubercles as described above; eyes large, occupying 

 about half of the lateral margin of the head (fig. A:\0k) 

 9 



8. Low but distinct dorsal hooks (best seen from lateral 

 view) present on abdominal segments 7 to 9; apex of 

 lateral lobe broadly rounded; lateral anal appendages 

 less than half the length of the superior (fig. 4:12A) 



Nasiaeschna Selys 



Dorsal hooks absent on all abdominal segments; apex 

 of lateral lobe truncate; lateral anal appendages more 

 than half the length of the superior . Epiaeschna Hagen 



9. Lateral spines present on abdominal segments 6-9 



Aeshna Fabricius 



— Lateral spines present on abdominal segments 3, 4, or 



5-9 10 



,10. Hind angles of head strongly angulate (fig. 4:10A) . . 11 

 i — Hind angles of head rounded or slightly angulate ... 12 



11. Lateral lobe of labium obtuse or subtruncate at tip; 

 median border of lateral lobe with distinct, more or less 

 square-cut teeth (fig. 4:11/) Boyeria MacLachlan 



j — Lateral lobe of labium with a taper-pointed tip; median 

 border of lateral lobe with indistinct denticulation 

 (fig. 4:11<7) Basiaeschna Selys 



12. Superior anal appendage nine-tenths length of inferiors; 

 inferiors strongly incurved at tips 



Oplonaeschna Selys 



Superior anal appendage about three-fourths as long 

 as inferiors Aeshna Fabricius 



Genus Anax Leach, 1815 



Four species of the cosmopolitan genus Anax occur 

 in the United States. One of these, A. Junius (fig. 

 4:28), is widespread and common in North America, 

 but the others are more southern in distribution. 



Adults are commonly known as green darners. They 

 are large and very strong fliers. Anax walsinghami 

 is the largest of our North American dragonflies, with 

 a wing length up to five inches and a length up to 

 nearly ten inches. 



Eggs are inserted beneath the water into the water- 

 isoaked stems of reeds or other plants or floating 

 sticks. The slender, green and brown naiads are 

 active climbers on submerged pond vegetation and 

 also move by ejection of water from the respiratory 

 chamber. They are notoriously cannibalistic. 



Key to California Specie* 



Male* 



1. Superior appendages not bifid; iibdomen 47-58 mm. long 



(North America, Central Amerioa, Weat indies) 



Junius (l)rur\ ) 1 77.') 



— Superior appendages bifid; abdomen 100-116 nun. long 

 (California, Utah, and Texas to Central fanerioa) . . . 

 walsinghami MacLachlan 1882 



F e mo les 

 1. Occiput with 2 blunt teeth on hind margin 



Junius (Drury) 

 — Occiput without teeth walsinghami MacLachlan 



Naiads 



1. Lateral lobes of labium tapering to a hooked point; no 



teeth on mentum on either side of median cleft 



Junius (Drury) 



— Lateral lobes of labium squarely truncate, a little 

 rounded on the superior angle; mentum with small teeth 



on either side of the median cleft 



walsinghami MacLachlan 



Genus Aeshna Fabricius, 1775 



The original spelling of Aeshna, rather than Aeschna, 

 as used by many workers, is retained because of a 

 ruling by the International Commission on Zoological 

 Nomenclature. 



Adults are strong fliers, usually blue and brownish 

 in color, and they are often commonly called blue 

 darners. Features of the coloration are often indistinct 

 in specimens that are not dried rapidly. 



They are found most abundantly near waters in 

 which they breed, but they may wander far inland, 

 particularly shortly after maturity. Generally, the 

 imagoes follow no regular course but fly up and down 

 over marshes and sluggish streams, shallow lakes, 

 ponds, or bays containing vegetation. In hot weather 

 the adults have a tendency to hang in the shade from 

 the underside of leaves of trees. Two species of 

 Aeshna have been recorded as swarming. 



Females oviposit soon after becoming fully mature 

 and continue to do so from time to time throughout 



Fig. 4:28. Wings of Anax Junius (Needham and Westfall, 1955). Fig. 4:29. Wings of Aeshna juncea (Needham ond Westfall, 1955). 



