NEUROPTERA— ODONATA— AGEIONINA. 1 39 



inates rather less than half-way from the nodus to the pterostigma ; the sub- 

 nodal terminates quite beyond the extreme tip of the pterostigma, the 

 median below its tip, the short sector, which ends in a zigzag course, before 

 the pterostigma and below the origin of the ultranodal ; the superior sector 

 of the triangle, which is straight to the tip, midway between the origin of 

 the nodal and the pterostigma ; and the inferior sector of the triangle, which 

 becomes zigzag a little beyond the nodus, terminates a little before the last. 



Length of wings, 21.3"""'; breadth, 4!6™"'; distance from nodus to base, 

 7.25"""; toarculus, 3 4"™; to center of pterostigma, 12.5"'"'; breadth of head, 

 3.5"""; diameter of eyes, 1.25™"; length of thorax, 5"'™; of femora, 3"™ ; of 

 tibial spines, 0.25"'™; of abdomen (seven joints), 24.5°'™; of first joint, 0.6"""; 

 second, 1.8™™; third, 4.4™™; fourth, 5™™; fifth, 4.6"™; sixth, 4.6™™; seventh, 

 3.4"™; width of last, 1.2™'". 



While the venation of the wing proves that this insect belongs in the 

 legion Agrion, the unusually short petiolation of the wing shows that it 

 can not be referred to Telebasis, and the short spines of the tibiae that it can 

 not be an Argia. To which of the numerous subgenera of Agrion it should 

 be referred can not be determined at present, but from the apparent want of 

 postocular spots and the early origin of the inferior sector of the triangle 

 it would appear to be most nearly allied to Amphiagrion or else to Pyrrho- 

 soma or Erythromma. If to the former its affinities are with tropical 

 American forms ; if to the latter with temperate forms of either hemisphere 



Florissant. Two specimens, Nos. 6824, 7158. 



2. Agrion exsulaeis. 



PI. 13, Fip. 6. 



A single nearly perfect wing differs so slightly from A. mascescens 

 that it would appear to belong to the same restricted genus, although from 

 our ignorance of the length of its tibial spines it might be considered an 

 Argia. The wing, which is apparently an upper one, is a little depressed 

 at the nodus, the antenodal portion of the costal margin being somewhat 

 arched, hyaline Avith black veins, the pterostigma normal, rhomboidal, 

 slightly longer than broad, the outer and inner margins considerably 

 oblique, the outer perhaps the more so, fuliginous, margined, especially 

 witliin, with heavy black veins, surmounting rather more than one cellule. 

 The inferior sector of the triangle originates before the basal postcostal nerv- 



