. Annual report of the Regents. New York State Museum; Science. 496 NEW YORK STATE MUSEUM Helocordulia is most nearly allied to Tetragoneuria. There are however a few venational characters which readily distinguish the two genera. CHABACTEE TETRAGONEURIA HELOCORDULIA 2d cubito-anal cross vein absent nearly always present Uuder the stigma a single cross vein fol- lowed by a wide space two cross veins and more normal spaces Autenodal cross veins of the hind wing four or five six The anal loop is slightly wider and more oblique at the apex in Tetra- goneuria. has the antenodal cross vei
. Annual report of the Regents. New York State Museum; Science. 496 NEW YORK STATE MUSEUM Helocordulia is most nearly allied to Tetragoneuria. There are however a few venational characters which readily distinguish the two genera. CHABACTEE TETRAGONEURIA HELOCORDULIA 2d cubito-anal cross vein absent nearly always present Uuder the stigma a single cross vein fol- lowed by a wide space two cross veins and more normal spaces Autenodal cross veins of the hind wing four or five six The anal loop is slightly wider and more oblique at the apex in Tetra- goneuria. has the antenodal cross veins spotted with fuscous much as in Helocordulia. The nymph of Helocordulia is pecuHar among the known cor- duline nymphs in having dorsal hooks on segments 6-9 only, with some. Fig. 21 Helocordulia, genitalia: a;, y ( ^ ) and 2; ( $ ) of H. uhleri Selys: a, b (ventral view), c ( 5 ) and d ( $ ) of H. selysi Hag. of these distinctly cultriform, and in the extreme abbreviation of the ninth abdominal segment on the dorsal side, so that its dorsal length is less than half its ventral. The two species of the genus may be separated as imagos by reference to the figures herewith presented. The nymph is known for but one of these, H. uhleri, the only one apparently belonging to the New York Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original New York State Museum; University of the State of New York. Board of Regents. Albany : J. B. Lyon, State Printer
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