PERLID.E. — ISOGENUS. CHLOROPERLA. 137 



decreasing in size and length : palpi nearly equal, maxillary five-jointed, 

 the two last joints short, more slender than the others ; labial three- 

 articulate, the apical joint very short and slender : labrum transverse, linear, 

 rounded in front : head large, depressed, transverse-quadrate : eyes very 

 prominent: ocelli three, placed triangularly; coZ/ar transverse: meso- and 

 meta- thorax tubercular : wings alike in the sexes ; anterior elongate-elliptic, 

 rounded at the apex, as long as the setae. 



From the circumstances of the sexes being similar in habit, by 

 both possessing ample wings, I think Mr. Newman has acted 

 judiciously in dividing this genus from the preceding, although in 

 other respects the structure is very similar to that of Perlag ; the 

 insects are, however, of a more slender form, approximating to those 

 of the following genus, likewise divided by Mr. Newman from Perla, 

 but forming a beautifully-intermediate link in the chain of affinities : 

 the palpi appear to be of nearly equal length, the labrum more 

 rounded in front, and the antennae shorter than in Perla. 



Sp. 1. nubecula. Plate xxxi. f. 4. — Alis anticis sordide hyalinis, nubecula 

 costali ultra medium fused. (Long. corp. 7§ lin. ; Exp. Alar. 1 unc. 3 — 5 lin.) 



Is. nubecula. Ent. Mag. (Newman) v. i. p. 415. — Steph. Nomen. 2d edit. 

 Appendix. 



Dark brown : head and thorax with a longitudinal ochreous line ; anterior 

 wings hyaline, slightly tinged with brown, and having a little oval cloud of 

 a darker brown on the costal margin, situated about one-third of the distance 

 from the tip towards the body; posterior wings beautifully hyaline, 

 iridescent ; legs pale brown. 



The oval cloud on the costa of the anterior wings is sometimes indistinct, as 

 in the example figured. 



Mr. Newman, to whom I am indebted for this species, says that it 

 is abundant in the neighbourhood of running waters in Herefordshire, 

 Worcestershire, Nottinghamshire, &c. and is the favourite food of 

 trout and grayling. 



Genus XXVIII.— CHLOROPERLA, Newman MSS. 



AnienncE remote, rather slender, as long as, or longer than, the body, composed 

 of numerous joints, the basal one large, the next smaller, the remainder 

 gradually smaller and shorter : palpi dissimilar ; maxillary elongate, the 

 two last joints most slender, the terminal one shortest; labial short, the 

 apical joint short and slender : labrum small, linear, straight in front : head 

 broad, considerably depressed : eyes prominent : collar ample, transverse- 

 quadrate: meso- and meta- thorax unequal : wings ample, mostly tinged with 



Mandirulata, Vol. VI., AucxUsx 15tii, 1836. s 



