352 



BRITISH SPECIES 



[CH. XVIII 



Tribe Sympetrini. Larva of type in fig. 36 o. Mask much as in 

 lini, the crenulations excessively flattened, the lateral lobes very warty. 

 Abdominal dorsal spines small. 



Sympetrum striolatum. Length 16-5. Large lateral spines on segs. 8 9. 

 Mask with 12 14 mental, 11 lateral setae. (The other species have not been 

 definitely determined.) 



Tribe Leucorrhiniini. Larva resembling that of Sympetrini, but with the 

 occiput narrower. Strong lateral spines on segs. 8 9 of abdomen, small dorsal 

 spines on segs. 4 5 (Leucorrhinia dubia). 



ZYGOPTERA. 



Family Calopterygidae. Larva of type in fig. 40. Mask with very deep 

 median cleft (fig. 32 B). Caudal gills : lateral long, triquetral ; median short, 

 lamellar. 



Calopteryx virgo. Pedicel of antenna 3-5 to 3-8 mm. long. Lateral 

 gills 9 mm. (fig. 40). 



Calopteryx splendens. Pedicel of antenna 4 to 4-2 mm., stouter. Lateral 

 gills 12 mm. 



Family Lestidae. Larva of type in fig. 41 B. Mask with setae on the 

 movable hook (fig. 32 H). Caudal gills long, lamellar, tips rounded (fig. 84 B) 

 (Lestes). 



The two British species have not yet been determined with certainty. 



Family Agrionidae. Larvae of type in fig. 42 D, E. Mask of type in 

 fig. 32 F. 



Length No. of setae on mask 



+ Gills Mental Lateral Caudal Gills General Remai 



Species 



Platycnemis pen- 11-5 + 7 

 nipes 



Ischnura elegans 13-5 + 6-5 



Agrion pulchellum 13-5 + 5 



mercuriale 13-5 + 3-3 



puella 14+5-5 



Erythr&mma najas 18 + 7-5 



Pyrrhosoma nym- 11-5 +4-8 

 phula 



Enallagma cyathi- 14 + 6 

 gerum 



5 

 5 



5 

 6 



6-7 



Caudal Gills 



Long, opaque, very Stout, dark, lo 

 pointed legged, slugg 



muddy 



Subnodate, point- Variegated green 

 ed, transparent yellow, active, 



weeds 

 Nodate, tip rounded Rather opaque, d 



brown 



Denodate, short, Opaque ochrec 

 pointed sluggish 



Nodate, very slight- Rather transpare 



ly pointed grey -green 



Nodate, transpa- Rather transpare 



rent, rich branch- greenish 



ing of tracheae 



Denodate, opaque, Broad, short, bro> 



broad triangular ish, sluggish, mi 



tip . dy 



Subnodate, trans- Pale green or ycll< 



parent, bluntly slightly market 



pointed 



(The other species have not been satisfactorily determined.) 



