AQUATIC INSECTS IN NEW YORK STATE 



U7 



Fig. 2i Pupa of Slalls Infumata x3 

 (After Needham) 



from water [fig. 22]. MialTs observations of S. lutaria 



quite agree with this, and he further states that the adult 



■emerges after two or three 



weeks. 



Adults. These have already 



been described above. They are 



very awkward fliers and are 



easil}" caught even without a 



net. This quite agrees witli the 



generalized form of the wing 



venation [fig. 23]. In fact, the 



adults when approached, will 



often run rather than attempt 



to fly. It is probable that 



the insect lives in the winged 



form only a few days. All 



ijpecimens taken were found 



to die within three days. The 



■dates on which the adults 



have been collected near Ithaca 



range from May 13 to June 



16, through a series of years. 



They are diurnal in their 



habits and seem to prefer bright sunshine. I have found them 



most abundantly in their egg-laying places at midday, though 



they also frequent the same places and are active till almost 



dark. 



The short life taken with the fact that the mouth parts of 



the adult are very poorly developed, would indicate that the 



adults do not take food. It 

 was reported to Dr Hageu and 

 to the national museum some 

 years ago that the adults of 

 S. 11 e V a d e n s i s were very 

 injurious to grapevine leaves. 

 This is the only case of injury 

 yet charged to any members 

 of the family, and may be a 

 false charge. On the other 

 hand, the adults, flying near 



the surface of w'ater, serve as an abundant supply of food for 



iishes. 



KEY TO SPECIES OF SIALIS 



■a Body and wings black or blackish 



6 Head black with flat, shining streaks and spots 

 yellowish 



Fig. 23 Fore wing of Slalls Infumata x4 



