208 EEV. A. E. EATON ON EECENT EPHEIMEEID^ OE MATTLIES. 



opaque view very light yellow-ochre, with the ungues and, in a less degree, the distal 

 edges of some of the tarsal joints light purplish brownish ; in transmitted light the ochre 

 changes to very pale amber. Wings vitreous, with bistre-, or light pitch-brown neuration ; 

 the principal nervures towards the base, and (in some lights only) the costa, subcosta, 

 radius, and some other of the longitudinal nervures, to a larger extent paler. Length of 

 body or wing 12, setoe upwards of 17 mm. 



Hah. North America ; Arizona (M°Lach. Mus.). 



Chirotonetes siccus, Walsh. Plate XVIII. 33 d (genitalia c? ). 



XBaetis sicca, ! Walsh, Proc. Acad. Nat. Sc. Philad. (1862) 371 ; Hag., Proc. Ent. Soc. Philad. ii. 

 170 (1863) ; ! Walsh, op. cit. ii. 191-2, notes 10, 11 (1803). 



ISip/ilurus siccus, Etn., Traus. Ent. Soc. London (1871) 130 [after Walsh]. 



Suhimago hardly distinguishable from that of Ch. aridus ; but in the present species 

 the 6 oculi are contiguous during life. 



Imago. — 6 . Head light ferruginous. Thorax and abdomen piceous above, spotless; 

 setae pale gi'eenish white, usually with the joinings nari'owly fuscous, but sometimes only 

 so at the base ; forceps a little darker towards the tijis. Wings hyaline, with fuscous 

 neuration. Fore leg usually about § as long as the liody, rarely as long as it, variable in 

 coloration, commonly piceous, with the tip of the tibia and the base and tip of the 1st 

 tarsal joint (which elsewhere is conspicuously pale) black or fuscous, and with the 

 remainder of the tarsus entirely fuscous, excepting rarely the basal halves of joints 2 and 

 3, which in one example are pale. Hinder legs pale greenish, with the extreme tips of 

 the tarsi cloudy. [After Walsh.] — Eorceps-basis deeply, broadly, and somewhat squarely 

 excised behind, in such a way that the projections terminated by the forceps-Hmbs are 

 longer than broad ; the margin of the basis in the middle of the excision is produced 

 into a short subacute salient projection, which is concave beneath. Penis-lobes broad, 

 obliquely truncate, moderately acute at their outer distal angles. 



$ . Very similar to the 3 . Pore tarsus pale fuscous, Avith the first joint conspicuously 

 pale. Length of body 8-5-11-5; wing, d 9-11-5, ? 11-13; setae, 6 im. 19, ? im. 15 mm. 



Hah. North America ; Rock Island, 111. (Walsh), api^earing a month later than 

 Ch. aridus. Also North Carolina (M'^Lach. Mus.). 



Chiuotonetes (?) ouNATTJS, Etn. MS., in the writing of Plate XIX. 33 ? c (genitalia 6 ). 

 This species must be dealt with and descrilied in the Supplement as one of undeter- 

 mined genus. My discrimination of generical differences in the present Section (the type 

 of Sipldurus) has been matured very recently ; whereas the drawings and description of 

 the insect were made in the year 1876, and I have not subsequently seen a specimen. 

 The plate Avas lithographed in 1882. 



METAMONIUS, gen. uov. 



Illustrations. Adult (details), PI. XX. ?34 6. 



Adult. — Pore leg of 6 about If as long as the body ; tarsus a little more than twice 



