THE IMMATURE STATE OF THE ODONATA. 27 



20. BRACHYTRON PRATBNSE. 



Plate V. Fig. 1. 

 Mueller. Selys, Eevue Odonates, p. 115. 



Nyniplia skins, male and female. Length, .39 to 42 mm. ; breadth, 7 mm. 

 Locality, Vienna, raised by F. Brauer; raised by Mr. Heyer, Lueneburg; 

 Danzig, by Mr. Brischke ; Silesia from Charpentier. 



Long and slender. Head smaller in proportion than in the other Euro- 

 pean species, narrower behind, more convex on top. Eyes rather small, 

 placed at forward angles of head, prominent, and separated from occiput by 

 very curved line. The inner hind angles much produced and rounded, with 

 no appearance of facets, which occur in other species, with exception of ^E. 

 affinis, which wants facets in inner part of produced angle. Occiput longer, 

 hind angle sharper and notched behind at almost a right angle ; a spot on 

 each side of median line, Avhich forms a ridge ; polLshed bands on hind 

 angles. Antennae differ in having third joint only half lengtli of fourth. 

 Mask reaching middle legs, less gradually enlarged, enlargement being 

 chiefly of apical third ; more produced at middle third of front border, cleft 

 narrower, and comb of hairs longer. Palpus shorter, more denticulated ; 

 movable hoolv not meeting the base of oppo.site one, nearly as thick at base 

 as palpus. Prothorax small, a little wider than liind border of occiput, more 

 rounded behind. Stigmata uncovered. Processes not much separated ; an- 

 terior nearly twice as long as posterior. Legs shorter and stronger ; hind 

 less reachincj middle seventh sejrraent ; femora somewhat arcuated. Wing- 

 cases reaching fourth segment. Abdomen long, slender, broadest at middle, 

 tapering gradually, smooth ; four dark spots in middle of each segment, two 

 on each side, and near margin two polislied impressions. Segments nearly 

 equal in length, except tentli, wliich is somewhat shorter. Lateral spines 

 small on segments six to nine ; only indicated on sixth sometimes ; that on 

 nintli only one third length of tenth segment. Appendages short and l)lunt, 

 a little longer than segment ten. Inferiors cut obliquely, middle one nearly 

 as long, cut straight at tip, not notched. Lateral superiors nearly as long as 

 middle one, bluntly pointed. Male projection large, conical, rounded, more 

 than half lengtii of lateral superiors. Male genitals slightly marked ; female 

 valve not reaching end of ninth segment. 



The nymphaj described are the types of Hagen, Stett. Zeit, XIV. p. 268, 

 and Brauer, Neur. Austr. j). xvi. 



