180 Annals Entomological Society of America [Vol. IX, 



lilies are probably individuals which have emerged from pupae 

 which have been drifted away from the original breeding place 

 by the wind and waves, rather than individuals which have 

 voluntarily wandered from the place of emergence. 



The adults of N. maculalis are largely nocturnal in habit. 

 Occasionally, individuals may be observed in flight during the 

 day but, in general, the period of activity begins shortly after 

 dusk. During the day, they can usually be driven to flight by 

 walking through the water-lilies or in the vegetation growing 

 near the edge of the water, or by beating the undergrowth 

 fringing the beach near the water-lily zone. On calm, clear 

 days, adults are commonly found at rest upon the upper surface 

 of the water-lily leaves, but on windy days they usually seek the 

 undergrowth near the edge of the beach. They respond readily 

 to shght disturbances by short jfiights but observations both in 

 the field and in the aquarium lead the writer to believe that 

 voluntary flight during the day is not common. Females in 

 the breeding cages remain inactive throughout the entire day. 

 Diurnal flight is apparently at random and the selection of 

 objects of support a matter of chance. Only one constant 

 feature was observed, namely, adults never made long flights 

 away from the immediate vicinity of the water-lily beds. 

 Individuals, driven from resting positions, often flew over the 

 open water, never rising high above the surface, dropping 

 momentarily on the surface from time to time, but almost 

 invariably, after a flight of three or four rods, returning to the 

 same vicinity. Individuals which happened to fly out from 

 shore during a strong wind had difficulty in returning and were 

 frequently carried far out on the lake. 



The adult apparently suffers little if any from contact with 

 water. The usual position of the .pupa is such that, on emer- 

 gence, the adult is, of necessity, compelled to come to the surface 

 through a certain depth of water. Individuals flying over open 

 water, as described above, frequently drop momentarily on the 

 surface, taking wing again without difficulty. Individuals, 

 whose powers of flight have been exhausted, drop ultimately to 

 the surface and may rest there for a considerable length of time. 



Nothing was discovered concerning the feeding habits of the 

 adult. Individuals have Hved for days in an aquarium without 

 food but the possession of well-developed mouth parts points 

 rather definitely to a feeding habit. 



