206 EEV. A. E. EATON ON EECENT EPHEMERID^ OE MAYFLIES. 



Chirotonetes mancus, Etn. Plate XIX. 33 a (wings and legs). 



\\Isonychia manca, ! Etn., Trans. Ent. Soc. London (1871), 134, pis. iii. 4 [wing] & vi. 5, 5 « [detail]. 



Subimago {dried). — Wings light sepia- or Cologne- earth grey, lighter for some distance 

 inwards from the inner margin, with narrow dark borders to most of the cross veinlets. 

 Setae somewhat of a dull light yellowish ochre. 



Imago {dried). — ? . Head and notum of a colour inclining to light yellow-ochre 

 or light Roman-ochre, modified or toned down in a slight degree Avith light brownish; 

 the markings of the upjier surface of the head comprise narrow piceous orbits of the 

 ocelli ; a conspicuous triangular streak or piceous spot on each side of the vertex, which 

 extends from the base of the posterior ocellus, and in contiguity with the orbit of the 

 oculus, nearly halfway towards the occiput ; and a broad faintly defined median longi- 

 tudinal brown-ochreous stripe on the vertex, intersected lengthwise by a line of the 

 lighter ground-colour. Abdomen light ruf o-piceous ; venter spotless ; setae whitish 

 yellow-ochreous, sometimes with the joinings opaque, or light reddish, towards the 

 roots. Wings vitreous, with very light brownish neuration ; in some lights the cross 

 veinlets show out more strongly than in other lights. Fore femur in opaque view rufo- 

 piceous ; tibia less translucent than the femur, but otherwise concolorous with it ; 

 tarsus in opaque view light Vandyke-brown throughout in most of the specimens, but in 

 some of them the first joint to a large extent is lighter and more translucent than the 

 remainder. Hinder legs in opaque view dull greenish yellow, approaching yellow-lake, 

 changing in transmitted light to pale yellow-amber ; the ungues sometimes slightly 

 brownish. 



6 . Undescribed ; the specimens of this sex referred to this species in 1871 are Ameletm 

 dlssitus. Length of body, $ im. 7-12 ; wing 9-13 ; seta3 15-22 mm. 



Hab. North America ; W. Texas (Belfrage) and Montana (M'=Lach. Mus.), May to 

 July. 



Chirotonetes aridtts. Say. Plate XVIII. 33 e (genitalia 6 ). 



XBactis ar'ula, Say, Journ. Acad. Nat. Sc. Philad. viii. 42 (1839) ; Walk., List of Neuropt. Ins. in 

 Brit. Mus. part iii. 562 (1853) ; Lc Coute, Complete Writings of T. Say ii. 412 (1859) ; Hag., Smitlison. 

 Miscell. Coll. (1861) Synop. Neuropt. N. Am. 46 j ! Walsh, Proc. Acad. Nat. Sc. Philad. (1862) 370; 

 Hag., Proc. Ent. Soc. Philad. ii. 170 (1863) ; ! Walsh, op. cit. ii. 191, notes 8 & 192, note 11 (1863). 



XSiphlurus aridus, Etn., Trans. Ent. Soc. London (1871) 129 [after Walsh]. 



Subimago (after Walsh). — "Wings clouded with dusky, especially towards the tips; 

 the hind wings broadly bordered with fuscous along the terminal margin ; neuration 

 dusky, the cross veinlets edged with fuscous. Fore legs fuscous, excepting at the base 

 of the first and sometimes of the second tarsal joints." 



Imago. — <s {dried). " Head light ferruginous, with the orbit of the anterior ocellus 

 black behind, and those of the posterior ocelli black on the inner sides. Thorax and 

 abdomen piceous above, except the last segment ; segments 2-9 occupied severally on 

 each side by a pale ferruginous triangular or semicircular spot extending halfway from 

 tlie base ; venter piceous in the middle throughout its length ; setae pale greenish white ; 

 forceps sometimes fuscous towards the tips. Wings hyaline, with pale greenish hyaline 



