NORTH AMKRICAN ODONATA. 219 



X^.A.I^T II. 



CATALOGUE OF THE ODONATA OF THE VICINITY 

 OF PHILADELPHIA. 



Characters of the Major Groups. 



SUBORDEK I. ZYGOPTERA.— Front and hind wings similar in shape or nearly 

 so, usually elevated in repose; no menibranule ; with an unmodified 

 quadrilateral. Males with two inferior, terminal, abdominal appendages, 

 penis and its vesicle separate. Nymphs with three caudal tracheal-gills. 

 Family 1. Agrionidj-:.— Head transversely elongated ; eyes separated from 

 each other ; lateral lobes of the labium of two* joints, middle lobe bifid. 

 Females with genital valves. 



Subfamily 1. Calopteryginx.— At least five, and usually more antecubitals. 



Subfamily 2. Aqrioninse. — Two, occasionally three, antecubitals, wings stalked 

 at base, quadrilateral not cross-veined (except in the S. Amer. Anomisma). 

 SUBORDER II. ANISOPTERA.— Wings dissimilar, hind wings usually broader 

 at base ; horizontal in repose ; usually with a membranule ; quadrilateral 

 modified to form a cardinal cell (triangle) and a supratriangle. Males 

 with one inferior, terminal, abdominal appendage, penis and its vesicle 

 connected. Nymphs without caudal tracheal-gills. 

 Family 2. Aeschnid^e.— Triangles of front and hind wings of similar shape 

 (except in some Gomphinfe). Antecubitals of first and second series not 

 coincident, except the first and one other (the latter is variable in posi- 

 tion), which two are thicker than their fellows. Postcubitals in the 

 entire second series. Lateral lobes of the labium of two® joints. Males 

 often with auricles on 2, and the anal margin of the hind wings excavated. 



Subfamily 3. Gomphinse. — Head transversely elongated, eyes separated. Ab- 

 domen without lateral cariuse. Females without genital valves (except 

 in the legion Petalura). 



Subfamily A. Cordulegasterinae.—'H.eaA transversely elongated, eyes a little 

 separated, or meeting in a single point dorsally. Abdomen without 

 lateral carinje. Females without genital valves. 



Subfamily 5. Aeschni7ix.—H.iiai globose, eyes meeting on the top of the head 

 for a space. Abdomen with lateral carinse. Females with genital valves. 

 Family 3. Libellulid.e — Triangle of front wings with its long axis at right 

 angles to the length of the wing, triangle of hind wings with its long 

 axis coinciding with that of the wing. Antecubitals of first and second 

 series mostly coincident. No postcubitals in the nodal end of the second 

 series. Lateral lobes of the labium of onef joint. Head globose, eyes 

 meeting on the top of the head. Abdomen with lateral carinse. Females 

 without genital valves. 



* 1. e. II and tp of fig. 7, pi. II. t I- e. U of fig. 7, pi. II. 



TRANS. AM. F.NT. SOC. XX. AUGUST. 1893. 



