180 NEUROPTERA OF NORTH AMERICA. 



with a dorsal yellowish spot upon the seventh segment (adult 

 male) ; appendages black ; the inferior one half the length of the 

 superiors, quadrangular, broadly bifid ; wings hyaline, posterior 

 ones at base, with a triangular black spot ; base of the wings, in 

 the females, flavescent ; pterostigma short, quadrangular, black ; 

 membranule blackish-gray; 7 — 8 antecubitals ; 7 — 9 postcubitals; 

 three discoidal areolets. 



Length 32 millim. Alar expanse 52 millim. Pterostigma 2 

 millim. 



Hah. Wisconsin (Dr. Hoy); Chicago (Osten Sacken); Ohio 

 (Schaum); Massachusetts (Scudder). 



11. D. hudsonica. 



Libellula hudsonica Selys, Revue des Odonat. 53. 



Similar to Diplax dubia Yander Linden (perhaps its variety ?) ; 

 it differs in being smaller, the basal spot of the posterior wings is 

 small, the reticulation of the wings is less narrow ; the vertex is 

 yellow above ; the labrum is hardly margined with black ; the 

 teeth upon the inferior surface of the superior appendages of the 

 male are almost equal. (From the description of De Selys Long- 

 champs.) 



Length 27 millim. Alar expanse 46 millim. 



Hob. New Brunswick ; Hudson's Bay. 



12. D. dubia! 



L. dubia Selys ! Revue des Odonat. 50, 21. 



Black; front white, labium black, labrum white, margined with 

 black ; the vertex and a band before the eyes, black ; thorax ob- 

 scure brassy-green, with brown villosity ; dorsum with a subinter- 

 rupted, fulvous stripe each side; sides spotted with fulvous; feet 

 black ; abdomen slender, triquetral, the dorsum spotted with yel- 

 low, base spotted, and segments 6 and 7 with larger spots ; wings 

 hyaline, or fumose, sometimes with the base flavescent, anterior 

 ones with two basal points, and the posterior ones with a point and 

 triangular spot at base, black ; pterostigma quadrangular, nigro- 

 fuscous ; membranule cinereous ; eight antecubitals ; seven post- 

 cubitals ; three discoidal areolets. 



Length 37 millim. Alar expanse 58 millim. Pterostigma 2 

 millim. 



Hah. Europe. 



