THE 



AMEBIC AN NATURALIST 



Vol. XL June, 1906 No. 474 



OBSERVATIONS AND F.XPERIM i:\ ()\ DKVCON- 

 FLIES IN RIIACKISII W XVVAl 



RAYMOND C. OSBL'UN 



When we consider the j?reat variety and extent of adaptation 

 amon^ the insects, and especially when we recall the multitude of 

 aquatic and semi-aquatic species, it seems rather remarkable that 

 none of them has been able to take up marine life. Ilalobates, 

 one of the Hemiptera, is truly oceanic, a few si)ecies of Diptera 

 are known to live in sea water durinc; their hirval staire, a few 

 larval forms have been found below hiu'Ii tide where they would 

 be exposed to the sea water for a portion of tlie time, iiiid a num- 

 ber of adult insects, chieflv beetles, rano-e the sh.-ie lui<Hii<: their 

 food when the tide is out." 



In bracki.h ^^^^uv. hnu.-x,. „u,„n ^pM ic ^ aie Miiulaih fouiui, 

 l)elon(,nno: to nearly all tlie insect ordt^'s. It is a noteworthy fact 

 that nearly all of these are more eominoiily toiind breedincr in 

 fresh water and are not peculiar to l)rackish water conditions. 



While the occurrence of dragonfly nymphs in brackish ponds 

 must have l)een noticed many times by obsiM-vinir naturalists, 

 references in literature are exceedinuly scant. Mr. K. A. >chwartz 

 C'Preliminarv Remarks on the Insect Fauna of tlie (It. >alt Lake, 

 Utah," Can.^Enf., vol. 2.S), foinul rnmpl,. lixin- in a mixture of 



adds: "The^.same .pe( ue,e aUo n at Liah bake, whi.h i. 

 fresh water"; and the <'niineni authoriiy on the dia-'onfhes. Dr. 



