1898.] NATURAL SCIENCES OF PHILADELPHIA. 151 



about one-third shorter ; viewed in profile it is directed somewhat 

 upward and the superior margin is biemarginated in two places, 

 viz. immediately behind 

 the base and immedi- 

 ately in front of the 

 apex ; both emargina- 

 tions have curved out- 

 lines and the ante- 

 apical is the smaller of 

 the two ; the tip of the 

 appendage is slender 

 and curved upward. 

 The genitalia of the 



second segment are . *«g. 5. 



. ., , n Profile view, left side of the terminal abdominal 



very similar to those ot appendages of Ophiogomphus reductus n. ep.cf 



serpejitinus, especially x 15. 



as regards the penis, as figured in Monog. Gomph., pi. 5, f. 2. 

 Anal triangle of the hind wings 4-celIed. 



9 . The two " horns " of the occiput are much shorter, in one 



female the right horn is absent and the left 

 is represented merely by two black denticles. 

 Second and third tarsal joints superiorly 

 (externally) more or less yellowish. These 

 females consequently, as far as the colora- 

 tion of the abdomen and of the tarsi is con- 

 cerned, resemble the female from southern 

 Russia described on p. 81, Monog. Gomph. 

 Dimensions. — Abdomen $ 37.5 mm., 9 37- 

 39. Hind wing ^33-34, 9 35-37. 



From spinicomis Selys (Bull. Acad. Roy. 

 Belg.-2-xlvi, p. 437, 1878) described from 

 a single female, from the mountains north 

 of Pekin, these females differ by the absence 

 of a black line on the fronto-nasal suture, the 

 predominant color of the vertex blackish, the " horns " of the occi- 

 put bearing denticles as in serpentinus, not a single short spine, the 

 absence of the black median dorsal thoracic stripes, the isolated 

 position of the black antehumeral stripe. 



From 0. assimilis Schneider (Selys in Monogr. Gomph., p. 81, 

 1857), from Asia Minor, known from two males, these males differ 



Fig. 6. 

 Ventral view of the 

 inferior abdominal ap- 

 pendage of Ophiogom- 

 phus reductus n. sp. tf 

 xl5. 



