PLATYCORDULIA 173 
132. Platycordulia xanthosoma Williamson 
Wmen. ’08, p. 432: Mtk. Cat. p. 124. 
Length 46 mm. Expanse 75 mm. Okla. 
This is a yellowish dragonfly, with the abdomen darker than the thorax 
except at the ends. The eyes are contiguous for a distance about equal to the 
width of the vertex. The wing membrane is yellowish hyaline with diffuse, yellow 
spottings on most of the cross veins that lie in front of a line through triangles 
and subnodus, and around behind the stigma to the wing apex. The yellow 
overspreads the membrane of the interspaces at base, nodus and apex, spreading 
especially to rearward at base of hind wing. Membranule white, posterior third 
dark brown, this brown color in the hind wing broadly margining adjacent cross 
veins. 
Williamson obtained two male specimens (all that are as yet recorded 
for this species) at Wistar, Oklahoma, flushing one of them himself from 
some bushes which overhung the edge of the Pateau River. “Its flight 
and manner of alighting and its position at rest suggested a teneral 
Libellula.”’ 
28. NEUROCORDULIA Selys 
These are crepuscular dragonflies of non-metallic coloration. The 
wings have basal markings of brown. Both triangle and subtriangle of 
the fore wing are normally divided into three cells. There are two 
cubito-anal cross veins. Veins M, and Cu, diverge toward the wing 
margin. 
The nymphs are stocky, short legged and rather smooth. The head 
has a low rounded shelflike frontal ridge between the antennae and a 
pair of obsolescent tubercles on top. Its hind angles are obtusely 
The Known Nymphs 
Lateral Dorsal | Dorsal 
Species Length spines hooks hooks Described by 
of 9 of 3 of 8 
obsoleta 20 surpass erect low Ndm. ’01, p. 486 
abd. app. 
yamaskanensis 23 not so curved | absent | Walk. 713, p. 165 
angulate with the hind margin concave between them. The labium is 
short and wide, with 7 to 9 mental setae each side and 5 or 6 laterals. 
The teeth on the inner margin of the lateral lobes are semi-elliptic, and 
separated by deep incisions, almost as in the Macromiinae. The abdo- 
men is oval with sharp lateral margins. There is a row of prominent 
