176 



SCIENCE-GOSSIP. 



LARVAE-NYMPHS OF BRITISH DRAGON-FLIES. 



By W. H. Ndnney. 



(Continued from page 150.) 



C? O far as it has been possible to tabulate diag- 

 nostic characters it has been done in the 

 following synopsis, the systematic names used 

 being those given in Mr. W. F. Kirby's " Catalogue 

 of the Odonata " and my own paper on "Dragonfly 

 Names " in Science-Gossip for September, 1892, 

 with one exception. It being advantageous that 

 the incorrectly spelled iEshna, of Fabricius, should 

 be discarded, I retain Dr. Leach's name, Gomphus. 

 The characters will probably need alteration from 

 time to time as our knowledge of the species 

 increases. Reference to figures a, b and c, 

 Science-Gossip, page Si, will help to an under- 

 standing of the terms used in the table. 



Synopsis of Families, etc 



Larva-nymph usually hairy, short and thick or 

 flattened and wide ; breathing by abdominal con- 

 traction and dilatation ; thoracic spiracles not 

 hidden.— LIBELLULID^E. 



Head sub-quadrate; antennas seven-jointed; eyes 

 obconic, with small rounded projection, prolonged 

 backwards, far apart ; mask helmet-shaped ; legs 

 longer than body.— -LIBELLULINJE. 



Body slightly longer than broad, hairy ; wing- 

 sheaths short ; tail-points as long as tenth body- 

 segment ; middle line of body with tubercles ; no 

 side points. — libellula depressa. 



Head broad, prolonged backwards ; middle line 

 of body with bent spines ; no side points. — 



LEPTETRUM 4-inacilIatum . 



Body long, tapering ; eyes large, globular ; ab- 

 dominal extremity pilose ; side and lower pieces of 

 caudal apparatus long, about equal in length, the 

 middle one-third less. — orthetrum cancellatum. 



Head broad, crown hollow ; middle line of body 

 with bent hairy teeth, two last segments spineless ; 

 no side prickles.— leucorrhinia pectoralis. 



Crown of head arched ; body broad, nearly 

 circular, hairless, central line unspined, eighth and 

 ninth segments with short, straight side-prickles. — 

 sympetrum scoticum. 



Crown of head hollow ; other characters similar 

 to those of preceding species (?). — s. vulgatum. 



Head somewhat pentagonal, thorax forming 

 base ; eyes as in Libellula? ; body oblong, wide, 

 truncate at tip, nearly or quite naked, somewhat 



cylindrical ; central line of back hooked.; short 

 spines occur laterally.— CORDULIINJE,. 



Head short ; eyes small ; body oblong, wide, 

 truncate at tip, nearly naked ; tail appendages 

 short, but longer than last body segment. — 

 somatochlora metollica. 



Head larger than in the preceding species ; eyes 

 larger ; body shorter, ovoid. — cordulia jnea. 



Body long ; mask flattened as in Agrionidae, or 

 spoon-shaped as in Libellulidae ; thoracic spiracles 

 partly hidden by prothorax.— GOMPHIDiE. 



Antennae four-jointed, flattened.— GOMPHINM. 



Middle third of front margin of, mask, forming 

 a rounded lobe ; palpus not toothed, and without 

 terminal hook ; tarsal joints 2-2-3. — lindenia 

 forcipata. 



Middle third or front margin of mask without 

 lobe ; palpas toothed, and with sharp terminal 

 hook ; tarsal joints 2-2-3. — gomphus vulgatissimus. 



Mask, spoon-shaped as in Libellulas ; antennae 

 seven-jointed and filiform ; tarsi all three-jointed. 

 — cordulegaster annulcitus . 



Eyes prolonged backwards and inwards ; 

 antennae seven-jointed, filiform ; central caudal 

 appendage truncated. — sESCHNINxE. 



Head broader than long ; eyes large but less 

 prominent than in iEschna ; mask extending 

 beyond middle legs. — anax imperator. 



Head somewhat convex above, much narrowed 

 behind. — brachytron pmtense. 



Head large; eyes very prominent, at the fore- 

 angles of the head ; mask extending to middle legs, 

 produced in front to a rounded lobe. — .eschna. 



Abdomen with whitish hairs ; processes above 

 base of legs blunt, stout, of equal length. — je. 

 coluberculus. 



Leg-processes short, nearly equal in length, 

 enclosing a right angle. — je. cyanea. 



Anterior processes half the length of the posterior 

 and much smaller than in cyanea. — m. juncea. 



Processes long, sharp, widely separated. — je. 

 grandis. 



Processes enclosing an acute angle, anterior half 

 the length of posterior. — m. isosceles. 



Larva-nymph slender and long, breathing mainly 

 by tracheal-gills formed by three caudal lamellae ; 

 eyes globular, at hinder angles of head ; three 



