486 NEW YORK STATE MUSEUM 



NEUROCORDULIA 



No species of this genus has been taken within the limits of this state, 

 but the following one is regional, being distributed from Massachusetts to 

 Indiana. The nymph of the genus is unknown, unless the one described 

 below be it. That nymph described and figured by Cabot and indicated 

 as belonging possibly to this species, is L i b e 1 1 u 1 a p u 1 c h e 1 1 a. 



Neurocordulia obsoleta Say 



1839 Li 1) ell u la obsoleta Say, Acad. nat. sci. Phil. Jour. 8 : 28 



1839 Libellula polysticta Burmeister, Handb. ent. 2 : 856 



1861 D i dym o p s obsoleta Hagen, Synopsis Neur. N. Am. p. 136 



1873 Epitheca obsoleta Hagen, Bost. soc. nat. hist. Proc. 15 : 269 



1863 Cord ulia modesta Walsh, Eut. soc. Phil. Proe. 2 : 254 



1890 Epi thee a obsoleta Hagen, Psyche, 5:369, pi. 1, fig. 7-9 (critical 



notes, with figures of the accessory genitalia) 

 1893 Neuro c or duli a obsoleta Calvert, Am. ent. soc. Trans. 20:252 



(description) 

 1900 Neurocordulia obsoleta Williamson, Dragon flies Ind. p. 312 



This species seems to be everywhere rare. I have not seen it at 

 large. There are very few specimens in collections. It is very different 

 in many particulars from all the other Cordulinae. It is very desirable 

 that some one should rear it. The imago will be easily recognized by 

 the characters given in the table. I describe below a nymph from Penn- 

 sylvania which probably belongs here. 



Nymph. (Not grown) Measures in total length i8 mm; abdomen 

 8mm ; hind femur 5 mm ; width of head 5 mm, of abdomen 8 mm ; 

 length of body without antennae 17 mm. 



A singularly flat-bodied, short-legged nymph with exceptionally con- 

 tracted abdomen, smooth, blackish in color, with traces of paler bands on 

 the femora and tibiae. 



Head dorsally flattened, with a pair of low, submedian, vertical 

 tubercles, and a shelf-like, scurfy pubescent frontal ridge, as long as the 

 two basal segments of the antennae; antennae seven jointed; joint i 

 cylindric, 2, globular, these of equal length ; segments 3-7 slightly decreas- 

 ing in length to the conic seventh segment. Hind angles of the head 

 obtuse, but prominent posteriorly, overhanging the front of the protho- 

 rax ; hind margin of the head excavate between the hind angles. 



Labium short and broad, hardly extending posteriorly beyond the 

 bases of the fore legs; mentum broadly triangular, contracted at its base, 

 concave within, its sharp superolateral margins spinous at both ends; 

 median lobe moderately prominent, with a few minute spinules on the 

 front border of it, declined ; mental setae eight or nine, the three or four 

 innermost ones quite small each side; lateral lobes triangular, concave 

 within, its distal border cut in about seven semi-elliptic teeth, each armed 

 at its tip with two or three spinules , lateral setae five ; movable hook a 

 little longer and stronger than the setae, gently arcuate. 



There is a distinct occipital ridge on the rear of the head below the 

 level of the vertex, closely applied to a corresponding ridge on the front 



