542 NEW YORK STATE MUSEUM 



1) Hind angles of the bead rounded ; the median vein two branched ; anteu- 



nae with segments eularoed distally C h a u.l i o d e s 



bh Hind angles of the bead bearing a sharp angulation or tooth ; median 

 vein three-branched; segments of the antennae cylindric 



Cory dalis 

 Zarvae 



a The last abdominal segment produced in a long, median, laterally fringed 

 tail like process; a pair of lateral filaments on abdominal segments 1-7 



Sialis 

 aa Last abdominal segment bifurcated, the fleshy forks each bearing a pair of 

 hooks and a minute, external, lateral filament ; conspicuous lateral fila- 

 ments on abdominal segments 1-8 

 h Lateral filaments with no tuft of fine tracheal gills at their bases 



Chauliodes 

 hd Lateral filaments each with a tuft of fine tracheal gills at its base 



C ory dali s 

 SIALIS 



Alder fiy^ : orl fly 

 A single species of this genus is recorded from this state. 



Sialis infumata Newman 

 Smoky orl fly 



Plate 29, fig. 3 

 1838 Sialis infumata Newman, Ent. mag. 5 : 500 

 1853 Sialis infumata Walker, Cat. neur. ins. Brit. mus. 3 : 195 

 1861 Siaiis infumata Hagen, Synopsis Neur. N. Am. p. 188 

 1863 Sialis infumata Hagen, Ent. soc. Phil. Proc. 2 : 180 

 1863 Sialis infumata Walsh, Ent. soc. Phil. Proc. 2 : 261-62 (figure of male 



genitalia) 

 1892 Sialis infumata Banks, Am. ent. soc. Trans, (listed) 

 1888 Sialis infumata Howard, Insect life, 1:99 (Sialis larvae in pools 



with Simulium) 



This is a dusky brownish fly, often seen with wings closely folded sit- 

 ting on sedge leaves near quiet waters. It may be taken with the fingers; 

 but, if the fingers close too slowly, it will fall to the ground, kick vigor- 

 ously several times to push itself into some crevice or tangle of stems and 

 lie very quietly; then it will be difficult to find again. The collector may 

 take advantage of this habit by bringing his opened cyanid bottle up to 

 the insect from below. 



This species is widely and generally distributed over' the United States, 

 and is often very abundanr, specially westward. I have seen the grassy 



1 So called in England because often found on alders overhanging tranquil streams. 



