396 THE STONE-FLIES. 



Slow of movement as is this creature, and yet predaceous, feeding wholly on living insects, 

 the mode of obtaining its food seems to be rather a problem. The solution, however, is simple 



enough, the creature digging a pitfall, and lying 

 ensconced therein while the expected prey 

 approaches. 



The beautiful NEMOPTERA COA belongs to an 

 allied family of this order, and is remarkable 

 through the curious development of the hinder 

 pair of wings, a peculiarity which is repeated, 

 though not on so extensive a scale, in many of 

 the butterflies. 



Our accompanying full page engraving repre- 

 sents the MAY-FLY, or EPHEMERA, the best and 

 most familiar type of the family to which it 

 belongs, and which is scientifically called the 

 Ephemeridse. 



This insect has long been celebrated for its short space of life, a single day sometimes 

 witnessing its entrance into the perfect state and its final departure from the world. The 

 popular idea concerning these insects is, that the whole ot their life is restricted to a single 

 day. This, however, is an error, as they have already passed at least two years in their 

 preliminary stages of existence. In the larval and pupal states, they are inhabitants of the 

 water, and are fond of hiding themselves under stones, or burrowing into the muddy banks 

 Under the latter circumstances they make a very curious tunnel, something like a double- 

 barrelled gun. It is said that the larva feeds upon mud, and, as a proof of this assertion, 

 it may be mentioned that Swammerdam always found mud within those specimens which 

 he dissected. I can personally vouch for the accuracy of his remarks, but would not like 

 to assert that, although mud was always found in the stomach and intestines of those 

 larvse which I have dissected, it might not have been swallowed with the food rather than 

 composed it. 



The May-fly is peculiarly notable for a stage of development which seems to be quite 

 unique among insects. When it has passed through its larval and pupal state, it leaves the 

 water, creeps out of its pupa case, and takes to its wings. After a period, varying from one 

 to twenty hours, it flies to some object, such as the trunk of a tree or the stems of water- 

 plants, and casts off a thin membranous pellicle, which has enveloped the body and wings, 

 the dry pellicle remaining in the same spot, and looking at first like a dead insect. After this 

 operation, the wings become brighter, and the three filaments of the tail increase to twice their 

 length. Some authors call the state between the leaving the water and the casting the pellicle 

 the "pseudimago" state. 



Some of these insects are well known to fishermen under the names of green and gray 

 drake, the former being the pseudimago, and the latter the perfect form of the insect, which 

 is represented in the illustration. Sometimes these insects occur in countless myriads, 

 looking like a heavy fall of snow as they are blown by the breeze, and having on some 

 occasions been so plentiful, that they have been gathered into heaps and carted off to the fields 

 for manure. 



The Perlidse, known to anglers by the name of STONE-FLIES, belong to the Neuroptera. 

 Several species of the same family are popularly called Yellow Sally and Willow-fly. They 

 may be known by the large folded front pair of wings, and the two bristle-like appendages at 

 the tail. 



