S90 ACADEMY OF NATURAL SCIENCES 



spots, and on the posterior margin an interrupted band ; remain- 

 ing segments having the same markings as the third, together 

 with a large double lateral longitudinal spot, excepting the ulti- 

 mate and the caudal segments, which have only the posterior in- 

 terrupted band ; caudal segments two-thirds the length of the 

 preceding one ; anal processes as long as the two preceding seg- 

 ments, undulated, foliaceous, with a longitudinal line in the mid- 

 dle, dilated on the inner edge beyond the middle, near the inner 

 tip, hairy, and with a tooth, and rounded prominence ; at tip 

 rounded, with a prominent cylindric spine ; inferior process half 

 the length of the superior ones; feet piceous, or blackish; an- 

 terior thighs with a glaucous line behind. 



Length less than three inches. 



The third abdominal segment is remarkably c ontracted. The 

 posterior interrupted bands might be called rounded or qu adrate 

 epots, and are largest and more glaucous on the posterior seg- 

 ments. It resembles Libellula tenehrosa ? 



4. M. CLEPSYDRA. — Abdomen contracted near the base, with 

 interrupted bands ; anal processes foliaceous. 



Inhabits Massachusetts. 



This is so much like constricta S., that it may possibly prove 

 to be a variety. Nevertheless, the anal [13] appendices are 

 very different. These are foliaceous, oblong-oval, gradually nar. 

 rowed at base, with a small angle at tip ; upper side with a cari- 

 nated line ; caudal segment of the abdomen with an elevated 

 compressed tooth near its base above. 



Length less than three inches. 



The only individual I have seen was sent me by Dr. Harris. 



5. M. VINOSA. — Abdomen contracted near the base ; wings 

 very slightly tinged with ferruginous ; stigma yellowish ; pleura 

 with two bright yellow orbicular spots. 



Inhabits Massachusetts. Harris. 



Length over two inches and a half. 



Resembles depst/dra S., very closely, but it may be distin- 

 guished by the color of the wings and stigma, the bright orbi- 

 cular spots of the pleura, the yellow antennae, and the absence of 

 black markings in the summit of the frontal vesicle. The anal 



[Vol. VIII. 



