234 Transactions. — Zoology. 



which ahiiost immediately divides into two branches, which 

 again divide. At the first furcation of the upper branch there 

 is generally a semi-transparent whitish spot without any hairs, 

 called the "thyridium." The "inferior cubitus" is always 

 fine, and does not branch. At the point of its termination on 

 the inner margin of the wing there is another transparent 

 whitish spot, called the " arculus." The apical forks of the 

 sector and superior cubitus divide the extremity of the wing 

 into a number of apical cells, which are numbered from before 

 backwards. 



The larvae are aquatic, and live in cases formed of small 

 pieces of sticks or leaves or grains of sand, &c., fastened to- 

 gether by a silky secretion from a spinning-gland, which 

 opens on the second pair of maxillae. In a few the case is 

 formed of the secretion only. These cases are either fixed or 

 free. The larva inhabiting them is herbivorous, and very 

 unlike the imago. The pupa resembles the perfect insect, 

 becoming active before it changes into the imago. These 

 active pupae are often called " nymphs," 



Artificial Key to the New Zealand Geneea. 

 1. Length of the fore wing more than four times its greatest width. 



Hind wing elongate, acute at the apex. 



Fore wing linear . . . . . . . . Setodes. 



Fore wing lanceolate . . . . . . . . Oxyethira. 



Hind wing triangular, blunt at the apex. 



Tibial spurs 2.2.4 .. .. .. .. Pseudonema. 



Tibial spurs 2.2.2 .. .. .. .. Notanatolica. 



2. Length of the fore wing betiveen three and four times its greatest 



breadth. 



Hind wing triangular . . . . . . . . Leptocerus. 



Hind wing oblong. 



Length of hind wing more than three times its 



greatest breadth . . . . . . . . Hydrobiosis. 



Length of hind wing between two and three times 

 its greatest breadth. 

 Antennse strong ; tibial spurs 3.4.4.. . . Poly centr opus. 



Antennse slender. 



Tibial spurs 2.4.4: a transverse vein con- 

 necting the radius with the sector . . Psilochoreina. 

 Tibial spurs 2.2.4; no transverse vein con- 

 necting the radius with the sector . . Philaniscus. 



3. Length of the fore wing less than three times its greatest breadth. 



Tibial spurs 2.4.4 



Last joint of the maxillary palpi like the others. 



Upper edge of the discoidal cell straight . . (Econesus. 



Upper edge of the discoidal cell excised . . Pseudceconesus. 

 Last joint of the maxillary palpi composed of many 



jointlets .. .. .. .. .. EydropsycJie. 



Tibial spurs 2.2.2 



Tibial spurs hairy . . • . . . • . Olinqa. 



Tibial spurs not hairy .. .. .. .. Pycnocentria. 



