372 CHAPTER OF VARIETIES. 



ON THE MAY-FLY. A very mistaken notion is prevalent in most 

 places with regard to the insect so well known to fishermen by the 

 name of the may-fly ; and until very lately I also acquiesced in the 

 popular error. 



Most people, I believe, imagine that the cadis, which is to be found 

 at the bottom and sides of every streamlet, is the may-fly in an imper- 

 fect and undeveloped state, and many fly-fishers, as well as other per- 

 sons, are not aware of the incorrectness of the supposition. The grub 

 from which the may-fly is formed, is to be found under the weeds which 

 grow at the bottom of rivers, buried in a fine green sand, and present- 

 ing in every respect an accurate resemblance both in the head and tail 

 to the perfect fly ; the growth of the. wings being indicated by small 

 pointed substances like the wing-cases on the back of an earwig. 



The cadis, on the contrary, when drawn from its covering, does not 

 present either in its head or tail any similarity to the body of the may- 

 fly, nor is there the slightest appearance of the growth of wings ; and 

 this is the case not only in February, March, or April, but even after 

 the may-fly has been some time on the water ; neither is one cadis ever 

 found in a greater state of forwardness than another, excepting as far 

 as regards its size, which would not be the case if the fly was formed 

 from that grub. 



Besides which, numbers of cadis are frequently found in places 

 where it is notorious that the may-fly never rises at all ; and that sim- 

 ple fact I should consider as a conclusive argument. 



Perhaps it may be as well to state that one of the members of the 

 fishing club at Stockbridge has caused the keeper to send a number of 

 the may-fly grubs up to London in a box, that the truth of this asser- 

 tion may be apparent. D. M. Devizes, 12th May. 



ON THE PECTINATED CLAWS OF HERONS AND NIGHT JARS. 



Having observed, in the last number of the Library of Entertaining 

 Knowledge, entitled " Habits of Birds," the various conjectures of 

 naturalists as to the use of the pectinated claws of certain birds, my 

 attention was recalled to the subject to which it had been directed some 

 time ago, when examining a bittern (Ardea stellaris) by finding in its 

 stomach a number of the large water beetle (Dytiscus marginalis ?). 

 It struck me at the moment that the comblike structure on the claw 

 was solely intended for disengaging the hooked feet of beetles from the 

 bill, to enable the bird to swallow these insects. It appears to me 

 indeed, that no better instrument could be devised for the purpose ; the 



