THE IMMATURE STATE OF THE ODONATA. Oa 
20. BRACHYTRON PRATENSE. 
Prate V. Fie. 1. 
Mueller. Selys, Revue Odonates, p. 115. 
Nympha skins, male and female. Length, 39 to 42mm. ; 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 AA. 
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, which forms a ridge; polished bands on hind 
angles. Antenne differ in having third joint only half length 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 hook not meeting the base of opposite one, nearly as thick at base 
as palpus. Prothorax small, a little wider than hind 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 
legs reaching middle seventh segment; 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 polished impressions. Segments nearly 
equal in length, except tenth, which is somewhat shorter. Lateral spines 
small on segments six to nine; only indicated on sixth sometimes; that on 
ninth only one third length of tenth seezment. Appendages short and blunt, 
a little longer than segment ten. Inferiors eut 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 length of lateral superiors. Male genitals slightly marked; female 
valve not reaching end of ninth segment. 
) 
The nymph described are the types of Hagen, Stett. Zeit. XIV. p. 268, 
and Brauer, Neur. Austr. p. xvi. 
