218 EEV. A. E. EATON ON EECENT EPHEMEEID^ OE MAYFLIES. 



of dots, and flanked in segment 8 by a longitudinally elongate spot, in segments 7-4 by 

 an obliquely elongate spot, and in segments 3-2 by an oblique linear stripe from the 

 posterior angle to tbe base, on each side ; segment 9 and the forceps-basis red-brown. 

 Setse whitish brown-ochre, with the joinings intense sepia-brown. Fore tibia and tarsus 

 dark reddish brown, the femur lighter, banded before the tip with dark reddish brown ; 

 hinder legs light brown-ochraceous, the femora with dark median bands. Wing vitreous, 

 perhaps suffused with a faint bistre-grey tint (but this appearance may be due to the 

 overgrowth of mould) ; longitudinal neuration pitch-black, the nervures towards the 

 base of the wing becoming somewhat of a bistre-brown ; the cross veinlets in the ptero- 

 stigmatic portion of the fore wing simple. Length of body, d 13 ; wing 14 ; setse 26 mm. 



Hab. Unknown. (Linn. Mus.) This may be an American species ; but there is one 

 rather like it in the Italian Alps, in the neighl)Ourliood of Monte Adamello. 



I have seen several other European species of Siphlurus. 



NORTH-AMERICAN SPECIES. 



Siphlurus occidentalis (renamed). Plate LXIV. 26 (forceps-basis). 



J Heptagenia % brunnea, ! Hag., Ann. Rep. U. S. Geol. & Geograph. Survey of the Terr. 1873, part iii. 

 Zool. 581 (1875) [ ? im. only]. 



Suhimago [dried). — Wings very light sepia-grey, with pitch- or dull raw-umber brown 

 neuration ; longitudinal nervures pale at the base. Setse pitch-brown with opaque joinings. 



Imu(jo (dried). — d . Notum piteh-l)rown, sometimes almost rufo-piceous along the 

 median sutui'c of the mesouotum. Dorsum of the abdomen bistre-brown, varied with 

 dull light ochraceous, nearly in the same manner as in S. tijpicus ; in segments 2-9 two 

 tapering streaks are projected from the darker colouring into the paler space on each 

 side of the segment ; the lower streak extends along the lateral border of the dorsum to 

 the base of the segment, and the upper streak, higher up on the side of the back, running 

 nearly horizontally, also attains the base ; the ligliter ground-colom' adjoining the dark 

 streaks remains in the form either of a pair of unequal triangular spots or longitudinal 

 streaks on each side of the base of the segment, of wdiich the lower streak is the larger, or 

 in the form of a single triangular spot corresponding with the lower of the two. Venter 

 very light brown-ochraceous with piceous markings, viz. : — in segment 9 a pair of broad 

 stripes, each tapering to a point behind, which meet in the middle of the base of 

 the segment at an acute angle, so as to form a V ; in segments 8-5 the corre- 

 sponding stripes combine at the base so as to form U-shaj)ed marks with oblique-pointed 

 arms ; in the more anterior segments their likeness to the letter U diminishes, owing 

 to increased obliquity in the stripes and consequent increase of width in the curves 

 resulting from their combination. The usual pairs of dark dots are recognizable, either 

 immersed in the ventral stripes, or else in contiguity with the inner edges of the stripes. 

 Forceps-basis and the proximal joints of the forceps-limbs usually pale, like the ground- 

 colour of the venter ; but the former is usually streaked with light brownish in the parts 

 overlain by the penis-lobes. Setse in opaque view either pitch-brown or raw-umber, 

 paler towards the tips. Fore leg in opaque view light pitch-brown, inclining to rufo- 

 piceous or burnt-umber. Hinder femora intense raw-umber, very slightly subopaque m 



