76 EEV. A. E. EATON ON EECENT EPHEMEEID.i: OE MAYFLIES. 



and higher than the head behind, but narrowed and sloping downwards anteriorly ; its 

 lateral borders, posteriorly, suddenly everted to a slight extent so as to originate a 

 strongly defined sinus or rounded depression on each side of the back ; its hind margin 

 curved ; in d the pronotum appears to be more appressed to the mesouotum, so that in 

 front view the hind margin seems almost retuse in the middle. Fore lep- of <3 about 

 half as long as the body, the tibia about 1| as long as the femur, the tarsus scarcely as 

 long as the femur ; 2 fore femur little shorter than the tibia, the tarsus scarcely f as 

 long as the tibia. Median setae in d extremely rudimentary, in $ not much shorter 

 than the others ; outer setse in d about 2^ as long as the body, in ? im. and d subim. 

 subequal in length with it; under a lens their surface appears minutely pubescent 

 throughout, and their joinings are inconspicuous. Last two joints of forceps-limbs 

 rather small. Lobes of penis nearly straight, subtubular, and somewhat tapering 

 distally ; the orifice of the seminal duct terminal ; no apparent stimuli. Abdominal 

 segments of $ : — 1 short and thoracoid, 2-6 gradually and successively longer, 7-9 nearly 

 equal to one another, but 8 perhaps a little the longest, and 9 a little longer than 7, 

 which is only a little longer than 6 ; segments 6-10 together constitute ^ of the abdo- 

 men. Anterior ocellus rather smaller than the others. Eyes of d nearly approximated 

 if not mutually contiguous above. 



Nymph unknown. 



Type. P. vittigera, Walsh. 



Distribution. Illinois and Texas. 



Etymology, vhre and 7ei'ea', from its being the fifth of the sections of Falingenia 

 anctomm, defined by Hagen in 1863, and named by Walsh in that year. 



Pentagenia vittigera, Walsh. Plate VIII. 13 (wings, legs, d & ? , forceps). 



Palmgenia vittigera, ! Walsh, Proc. Acad. Nat. Sc. Philad. (18G2), 373 ; Hag., Proc. Eut. Soc. Pbilad. 

 ii. 174 (1863). 



Pentagenia [type] vittigera, ! Walsh, op. cit. ii. 197 (18G3) ; ! Etn., Eut. Mo. Mag. v. 85 (1868) ; ! id.. 

 Trans. Eut. Soc. London (1871), 63, pis. i. 6 and iv. 1 [details]. 



Subimago. — " Wings dull opaque yellowish" (Walsh). 



Imago. — Eyes of the living d {teste Walsh) yellowish above, their lower \ fer- 

 ruginous. (Dried) d . — Body traversed from head to tail along the middle of the back by 

 a deep warm sepia stripe, containing in segments 1-9 of the abdomen the usual pair of 

 short divergent yellowish lines at the base of every segment ; sides and under parts of 

 the body chiefly light yellowish ochreous or Xaples-yellow, but segments 8-10 of the 

 abdomen are of a brighter yellow beneath, and on each side of the mesothorax a warm 

 sepia stripe descends from the roots of the fore wing obliquely. Legs, viewed opaquely, 

 very light yelloAvish ochraceovis, but in transmitted light of a yellowish amber-colour ; 

 fore tibia light brown-ochreous, the tarsus rather darker, the end of the tibia and the 

 extremity of the broader of the tarsal ungues warm sepia or burnt-umber brown ; hinder 

 tarsi with the ungues and the tips of the terminal joints tinged with bistre-brown. Wing- 

 neuration translucent, mostly colourless ; in the fore wing the great cross vein between 

 the subcosta and the radius, and a short linear spot at the bulla; of the subcosta and the 



