Notes on the Commoner Species 147 



immersion. These data do not by any means ap- 

 ply to all the other Culicid larvae, most of which are 

 far less resistant. 



Some calopus larvae four hours old were alive after 

 four hours of compulsory subaqueous existence, but 

 were apparently dead after four and a half hours. 

 They revived, however, on being placed in shallow 

 water; so did also a pupa, after eighty minutes. A 

 full-grown larva, re-animated after two hours under 

 water, pupated during the night, and the imago 

 issued about twenty-six hours later. 



This ability to stay under water for so long a time 

 will enable the larvae to nibble on the bottoms of 

 cisterns of the usual water depth in general use. Dr. 

 Dupree examined a number of cisterns, finding the 

 larvae feeding thus in many instances. I cannot 

 speak for New Orleans, but in Baton Rouge Stego- 

 myia is principally a cistern, tank, bucket and tub 

 breeder, and will also propagate in the house, lay 

 eggs in your water pitcher overnight, and 

 produce lusty crops of wigglers in flower vases 

 or flower-pot saucers if water be left long in 

 them. 



The larvae were sometimes observed feeding, of 

 their own volition, at the bottom and at the sides of 

 the vessel in which they were reared in the labora- 

 tory, for as much as two hours consecutively. This 

 applies more especially to very young larvae, whether 

 they " flood their air chambers," or whether their 

 anal gills sustain respiration while they are engaged 

 thus in diving, the Doctor would not venture an 

 opinion. Possibly the thinness of the skin at this 



