1978] Lilly, Ashley, & Tarter — Population of Sialis itasca 215 
Pupal Stage 
Larvae placed in the laboratory rearing chambers moved to the 
sand for pupation within 2 to 4 days. The pupal stage lasted for 
approximately 2 weeks. The adults emerged during the night. No 
pupae could be located in the bank of the pond. 
Azam and Anderson (1969) reported S. rotunda and S. calif ornica 
to pupate during April, May and June. Pritchard and Leischner 
(1973) reported that S. cornuta pupated from May to mid-June. 
Woodrum and Tarter (1973) found S. aequalis to crawl 1.5 to 5 m 
out of the water onto a moist sandbank when the water temperature 
reached 11 to 13 C and pupated in an earthen cell 1 to 7 cm below 
the surface. They found the pupae to respond to a disturbance but 
otherwise remained rather dormant. 
Adult Stage 
Number and Size of Eggs. — Fecundity of 3 adult alderflies 
showed a range of 454 to 587 eggs per female; the average was 539 
eggs. The eggs were cylindrical, rounded on the ends, had a curved 
micropylar tubercle on one end, and averaged 0.31 mm in length by 
0.14 mm in width. The number of eggs found in S. itasca was similar 
to those of S. aequalis (657) (Woodrum and Tarter, 1973), S. 
rotunda (300-500) and S. californica (400-700) (Azam and Ander- 
son, 1969), and S. cornuta (615) (Pritchard and Leischner, 1973). 
Egg masses of S. itasca were found on the underside of hornbeam 
and buckeye leaves 0.5 to 3 m above the water surface. The eggs are 
laid in rows in a nearly vertical position much like those of S. 
rotunda (Azam and Anderson, 1969). 
Mating. — Although copulation was not observed, a courtship 
behavior was observed in the laboratory much like that described by 
Azam and Anderson (1969) for S. rotunda and by Woodrum and 
Tarter (1973) for S. aequalis. 
Longevity. — Adults in the laboratory lived for 4 to 6 days. Only 
one adult was captured in the field on 3 May 1975. Sialis rotunda 
was first seen in mid-April and reached their peak in May (Azam 
and Anderson, 1969) while S. californica was seen in May but did 
not peak until mid-June (Azam and Anderson, 1969). Sialis aequalis 
was observed in the field between April 21 and May 4 (Woodrum 
