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POLYNEMA NATANS IN YORKSHIRE. 
A. R. SANDERSON, 
FROM a bog pool on Austwick Moss I have to place on record 
the finding of Polynema natans Lubbock (Caraphractus cinctus 
Hal.), a very small hymenopterous insect belonging to the 
Mymarides, which by Enoch are called ‘ Fairy Flies.’ Polynema 
natans, one of the few hymenoptera with acquatic habits, 
has a strange life history, being in the larval stage parasitic 

Polynema natans, and wing, magnified. 
in the eggs of a Dragon Fly. The specimens I obtained were 
present among some Hypnum fluitans, which had been brought 
from the bog pool to feed acquatic larve. A few days 
after introducing this material to the tank I saw two of the 
insects swimming about in the water, using their wings as 
organs of locomotion. This struck me as_ being decidedly 
curious, so I watched developments, and noticing the immersion 
was not harmful (at first I took them for small flies in process 
of drowning) kept them under observation. On examination 


Naturalist , 
