38 HAUSTELLATA. LEPIDOPTERA. 



Genus CCLXIV. — Hydrocampa, Latreille. 



Palpi four, maxillary distinct; labial ascending, slender, divaricating, the 

 basal joints densely clothed with elongate scales beneath; triarticulated, 

 the terminal joint acute: wax/Z/cp elongate. Antennae moderate, simple in 

 both sexes, curled and subserrated within at the apex, in the males slightly 

 ciliated; head small, smooth between the antennae: thorax moderate, 

 densely pilose : ivings ample, anterior elongate, somewhat acute, the hinder 

 margin entire ; posterior ovate-triangular, also with the hinder margin 

 entire ; the surfaces of all prettily reticulated, with dark duplex lines upon a 

 pale ground : abdomen elongate, annulated, with a tuft at the apex in the 

 males, very acute in the females : legs long and slender ; posterior tibise 

 with two pair of elongate spurs. Larvse slender, with 16 legs; subsist upon 

 aquatic plants; pupa inclosed in a cocoon cut out of their leaves. 



The pretty insects of this genus differ from Diasemia by having 

 the palpi slender and divaricating, the maxillary ones very distinct, 

 maxillae elongate, and the wings pale, reticulated with double brown 

 streaks ; the hinder margin is entire and faintly rounded, and the 

 antennae are subserrated at the apex. 



A. Labial palpi with the terminal joint short, scarcely exposed, the basal 



joints very scaly beneath : — Nymphula, Hilhner. 



Sp. 1. Potamogata. Alisalhis,fusconehidosis,Jasciissaturatioribusanastomo~ 

 santibus ; autfuscis alba maculatis. (Exp. Alar. 1 unc. 1 — 4 lin.) 



Ph. Ge. Potamogata. Linni,. — Donovan, xi. pi. 363. f. I. — Hyd. Potamogata. 

 Steph. Catal. ii. 163. No. 6799. 



Wings white, with fuscous clouds, and darker anastomosing (or reticulated) 

 streaks, the spaces between paler ; these streaks enclose three or four large 

 patches of white, of which a conspicuous ovate triangular one is placed 

 towards the apex of the inner margin, and a second large reniform one on 

 the costa behind the middle ; near the hinder margin is a simple but distinct 

 repanded line ; posterior wings with a duplex streak before the middle, and 

 one behind, leaving an intermediate white band in which is a brown crescent, 

 the outer portion of the hinder striga of irregular outline ; the hinder 

 margin itself with a simple line; cilia fuscous, sometimes clouded with 

 white. 



Extremely variable, some examples are almost entirely suffused with brown, 

 having a few conspicuous white patches; others are nearly white, and all 

 the intermediate shades occur. 



The caterpillar feeds on the white and yellow water lily {Nijinpha;a; alba et 

 lutea), and the broad-leaved pond-weed {ruianwgeloji, nutans) : the imago 



