134 



Smith and Pritchard: Odonata 



Fig. 4:53. Wings of Pachydiplax longipennis 

 (Needham and Westfall, 1955). 



Mississippi River and is found about ponds and slowly 

 moving streams. The hairy nymphs lie in the ooze at 

 the bottom of stagnant ponds. 



Genus Libellula Linnaeus, 1758 



These showy insects are among our best known 

 dragonflies. They are very common and hover about 

 ponds, tanks, marshes, canals, and sluggish rivers 

 or streams (fig. 4:44). The naiads are hairy and sprawl 

 in the bottom silt and trash. For the most part they 

 are fresh-water forms. The genus is Holarctic with 

 k most of the species occurring in the United States. 



Key to the California Species 

 Males 



1. Wing with a proximal dark band covering wing and 

 reaching nodus luctuosa Burmeister 1839 



— Wing with proximal marking much smaller or absent 



2 



2. Pterostigma bicolored (half brown, half yellow) (Cali- 

 fornia and Wyoming south to Mexico) 



comanche Calvert 1907 



— Pterostigma uniformly colored 3 



3. Fore wing without a proximal dark brown or black 

 streak; costa pale 4 



— Fore wing with proximal brown streak; costa dark. . . 5 



4. Hind wing with proximal dark spot having dark veins 

 (Wyoming to California and Arizona) 



composite. Hagen 1873 



— Hind wing with proximal dark spot triangular and with 

 yellowish veins (Holarctic) 



quadrimaculata Linnaeus 1758 



5. Wing with a large maculation in apical third (America 

 north of Mexico) pulchella Drury 1773 



— Wing without a maculation in apical third 6 



6. Wing with spot in middle third covering most of breadth 

 of wing (British Columbia to Montana south to Cali- 

 fornia) forensis Hagen 1861 



— Wing with median spot confined to small area around 

 nodus (Wyoming to California and south to Columbia 

 and Venezuela) nodisticta Hagen 1861 



Females 



1. Stigma bicolored comanche 



— Stigma uniformly colored 2 



2. Wing with a broad dark band proximally, covering wing 

 and extending nearly to nodus luctuosa 



— Wing with proximal marking much smaller or absent 



3 



3. Wing with maculation in middle third traversing over 

 one-half of wing 4 



— Wing with median maculation restricted to small area 

 around nodus or absent 5 



4. Wing with maculation beyond stigma pulchella 



— Wing hyaline distally forensis 



5. Fore wing with dark brown or black maculation proximal 

 to nodus nodisticta 



— Fore wing without dark proximal maculation 6 



6. Hind wing with proximal spot triangular with yellowish 

 veins; face yellowish quadrimaculatus 



— Hind wing with proximal spot with dark veins; face 

 white composita 



Naiads 7 



1. Head squarish seen from above, not narrowed behind 

 eyes; 6 deeply cut, sharply serrate teeth on lateral 

 lobes of labium; single raptorial seta on each side of 

 mental lobe; lateral setae 7-8 composita Hagen 



— Head narrowed behind eyes; 10 or 11 shallow, broadly 

 truncated teeth on lateral lobes of labium; mental setae 

 9 or more 2 



2. Dorsal hooks present on some middle abdominal seg- 

 ments 3 



— Dorsal hooks absent on abdomen; lateral setae of 

 labium 6 comanche Calvert 



3. Dorsal hooks lacking on abdominal segment 8; lateral 

 setae 5-9 4 



— Dorsal hooks present on segments 4 to 8; lateral setae 

 7 or more; mental setae 10 5 



4. Lateral setae of labium 5-7; mental setae 9-11 



forensis Hagen 



— Lateral setae of labium 8-9; mental setae 13 . 



pulchella Drury 



5. Lateral abdominal appendages about half as long as 

 inferiors; dorsal hooks present on segments 4-8 .... 



luctuosa Burmeister 



— Lateral abdominal appendages about seven-tenths as 

 long as inferiors; dorsal hooks present on segments 3-8 



quadrimaculata Linnaeus 



Genus Plathemis Hagen, 1861 



This genus, which is closely related to Libellula, 

 contains two common and widespread species, (fig. 

 4:45). They exhibit marked sexual dimorphism. They 

 occur near ponds and ditches and frequently are 

 seen hovering over the water or resting on plants 

 near shore. The females work in and out of sheltered 

 nooks nearby to lay their eggs. They drop twenty-five 

 to fifty eggs each time their abdomen strikes the 

 surface of the water. 



Key to California Species 



Adults 



1. Male with ventral process on abdominal segment 1 

 deeply bifid, wing with median crossband uniformly 

 brown (fig. 4:45); female with tip of wing black (wide- 

 spread in U.S. and Canada) lydia Drury 1773 



— Male with ventral process on abdominal segment 1 

 shallowly and broadly emarginate, wing with median 

 crossband subdivided by a paler band; female with 



The naiad of nodisticta Hagen is unknown. 



