THE STONE-FLY. 189 



many points of structure they exhibit striking differ- 

 ences from them. 



' If the little Atropos comes of its own accord to 

 visit the entomologist^ the remaining insects of the 



1 suborder Dictyotoptera are only to be found by going 

 in search of them, and their investigation will lead us 

 again to the water- side, from which we have been so 

 long absent, as they all pass through the stages of 

 larva and pupa in the water, and it is upon the plants 

 and other objects which fringe their birthplace, or 

 hovering upon their gauzy wings over its surface, 

 that we shall meet with the perfect insects. In such 

 situations, especially on the plants along the borders 

 of stony streams, we shall find as early as April a 

 fly, rather more than half an inch in length, of a 



j blackish colour, with a yellowish streak running 

 down the centre of the head and thorax; it is fur- 

 nished with long bristle-like antennae, composed of 

 numerous joints, with four pale wings traversed by 

 numerous strong brown veins, some of which are 

 united by transverse veinlets, and with a pair of 



I jointed bristles at the extremity of the abdomen, 

 which nearly equal the antennae in length, and closely 

 resemble them in structure. This is the well-known 

 Stone-fly of the angler, who often finds it an excellent 

 bait for trout, and some other fishes of less repute, 

 such as the chub ; its scientific appellation is Perla 

 bicaudata, and it forms the type of a peculiar tribe 

 of Neuropterous insects, to which we may give the 

 name of Perlina. 



The insects belonging to this group are easily 

 distinguished from all the other members of the 



