64 NEW YORK STATE MUSEUM . 



genera, etc. Since McLachlan's work appeared, much lias been 

 done towards obtaining a better knowledge of the family from 

 different points of view, and our information is now much more 

 detailed and exact with respect to the structure and morphologi- 

 cal value of the so-called appendages, this improvement being 

 largely due 1 to the more extended use of microscopical prepara- 

 tions in studying these insects; and something has also been 

 learned concerning the early stages of the lives of these tiny 

 creatures which, as larvae, construct curious habitations of 

 most diverse forms. As contributors to this knowledge may be 

 mentioned the names of Klapalek, Ris, and the writer of the 

 present notice. 



Quoting from McLachlan (op. cit. p. 503) : " The minute insects 

 comprised in this family may be justly termed Micro'-Trichoptera, 

 for the largest European form expands to no more than 10 mm., 

 the smallest to only 3J ruin. Where they occur they usually 

 swarm in great numbers, running with extreme rapidity, and 

 very difficult to capture. Although they occasionally appear to 

 delight in warm sunshine, they are more especially crepuscular 

 or even nocturnal, and are attracted by light to 1 such an extent 

 that the walls and ceilings of rooms near water are often dotted 

 with these dark atoms which have entered by open windows." 



The largest measurements are attained in Agraylea and 

 Allotrichia, no species of which is here described. The 

 average expanse may be set down as 5-7 mm., the females as a 

 rule being slightly larger than the males in a given lo'cality. 



The following table of the genera is taken from McLachlan's 

 Revision and Synopsis of European Trichoptcra, pp.504-5, with 

 the addition of a new genus which is described on p.72. 



A Wings broader, subobtuse, the posterior with no costal elevation or ex- 

 cision. (Neuration tolerably complete; spurs 0, 3, 4; ocelli present 



and distinct) . ? Agraylea 



B Wings narrower, often acute or subacute ; the posterior with a more or 

 less decided costal elevation followed by an excision 

 a Spurs 0, 3, 4 



& Ocelli present and distinct 



c Neuration tolerably complete Allotrichia 



cc Neuration less complete 



d Wings scarcely acuminate Ithytrichia 



dd Wings strongly acuminate Oxyethira 



&& Ocelli absent (wings acuminate) Orthotrichia 



