TIKKID.E. THERISTIS. 333 



Anterior wings subcaudate, of a griseo-testaceous hue^ with the costa pale, 

 and a longitudinal fuscous streak extending from the base to the apex, 

 where it coalesces with a deeper oblique fuscous line; in the middle of the 

 disc is a faint fuscous dot, and a row of minute griseous dots on the hinder 

 margin : posterior wing whitish. Female with the anterior wings narrower 

 and paler, and destitute of the longitudinal fuscous streak, having only faint 

 rudiments thereof. 



Rare : taken occasionally in the marshes within the metropolitan 

 district, most commonly in the vicinity of Dartford and Erith, in 

 June. 



Genus CCCLXX. — Theristis, Hiibner. 



Palpi four; maxillary short; labial moderate, incurved, clothed with extremely 

 long scales,projecting considerably beyond the terminaljoint,\vhich is pointed, 

 and is placed on the upper margin of the apparent middle : maxillw as long 

 as the palpi. Antenna; rather long, setaceous, slender, simple in both sexes ; 

 head narrow, produced in front into a conical form ; eyes moderate : thorax 

 subquadrate : ivings slightly convoluted during repose ; anterior very long, 

 slender, acuminated or falcate at the apex, generally pale, with some darker 

 longitudinal marks, and sometimes a dusky point towards the middle ; 

 cilia very short : posterior rather ample, faintly sinuated on the hinder 

 margin, cilia elongate: body slender, long, obtuse at the apex in the female, 

 with a small tuft in the males : legs long and slender, Avith two pair of long 

 spurs on the posterior ones. 



These insects may be known from the preceding genus, not only 

 by the form of their wings, the anterior especially, but by having 

 distinct rather long maxilla? ; their colours are generally of a pale 

 hue, with longitudinal darker markings, and a central dusky point : 

 during repose, they sit with their wings convoluted slightly, and a 

 little deflexed, with the antenna:} porrected forwards like the Porrec- 

 tarite : they frequent grassy places. 



Sp. 1. Acinacidella. Plate 40. J- 1. — Alis anticis longissimis ochraceo-stra- 

 mineis, atomis linelque longitudinali subimpressj nigris, posiicis albidis 

 nitidis. (Exp. Alar. 1 unc. 2 — 4lin.) 



Ti. Acinacidella. Hiibner.— Vh. Acinacidella. Sfeph. Catal. ii. 222. A'b. 7505. 



Anterior wings very long, narrow and acute, of a pale ochreous-straw colour, 

 with a longitudinal somewhat impressed black line at the base, and nume- 

 rous black atoms remotely scattered on the disc, one of which, towards the 

 base of the streak, is rather large: posterior wings whitish, shining, with 

 very long straw-coloured glossy cilia. 



