MAY-FLIES. 27 



flies is remarkable. Swarms consisting of millions of 

 individuals are occasionally witnessed. In the perfect 

 state these insects are a favourite food of fishes, and most 

 of the "duns" and "spinners" of the angler are rude 

 representations of Ephemeridee. Ronald says * that the 

 term " dun " refers to the sub-imago condition, " spinner " 

 to the perfect insect. 



These sensitive creatures are unable to resist the 

 attractions of artificial light ; and since the introduction 

 •of the electric light, accounts often appear of myriads 

 being lured by it to destruction. Their dances may 

 frequently be observed to take place in peculiar states of 

 light and shade, in twilight or where the sinking sun has 

 its light rendered broken by bushes or trees ; possibly the 

 broken lights are enhanced in effect by the ocular 

 structures of the insects. 



That insects so fragile, so highly organised, with a host 

 ■of powerful enemies, but themselves destitute of the 

 means of attack or defence, should contrive to exist at all 

 is remarkable ; and it appears still more unlikely that such 

 •delicate insects as Ephemeridce should leave implanted in 

 the rocks their traces in such a manner that they can be 

 recognised ; nevertheless such is the case, and the May-fly 

 palaeontological record is both rich and remarkable. 

 From the great variety and large size of many of the fossil 

 May-flies, Scudder considers that the fragile, short-lived 

 May-flies of the present day must be regarded as the 

 lingering fragments of an expiring group. 



Genus ICHTHYBOTUS, Eaton (1899). 



"A genus of the sectional type of Ephemera, resembling Pentagenia in 

 style of wing-neuration, and in having the median caudal seta abortive in 

 the male imago, but either not much shorter than or subequal in length to 

 the outer setae in the female. Legs as in Ephemera, excepting the claws of 

 the fore-tarsus of the male, the outer claw being hooked and the inner obtuse. 

 Distinguished from the other genera of this sectional type by the male genital 

 forceps, resembling in pattern those of a Siphlurus (cf. -S'. lacustris), the 

 forceps-basis sub-quadrate with the posterior angles obliquely truncate for the 

 insertion of the limbs, the first joint in which is shorter than the basis. The 

 name in Greek means fed on by fish." f 



ICHTHYBOTUS HUDSONI. 

 Ephemera hudsoni, McLachlan, Ent. Mo. Mag., 1894, 



* " Fly-Fisher's Entomology," 4th ed., 1849, p. 49. 

 f Trans. Ent. Society of London. 1899, p. 285. 



