156 NATURAL HISTORY OF ARTHROPODS. 



female during the act of pairing; hence, during its short life, the male, at least, proba- 

 bly takes no food. 



After pairing, which occurs in the middle of summer, the female deposits her eggs, 

 to the number of about three thousand, in flat, rounded masses, on trees overhanging 

 water, etc. On breaking forth from the egg the young larva readily finds its Avay into 

 the water, and descends to the bottom. It undergoes six moults before pupal life. 



The fully grown larva is as large an insect as is to be found in our streams, and it 

 is a very singular creature. It crawls actively about, seeking smaller aquatic worms 

 and larval insects, which it snaps up and tears to pieces with its large toothed jaws. 

 It can breathe both out of and in the water, since besides a series of spiracles on each 

 side of the body it possesses eight pairs of bushy breathing appendages, or gills, with 

 a long supplementary filament, which it ordinarily uses while in the water. The spi- 

 racles come in play late in larval life, as it lives several weeks out of water before 

 seeking its cell, within which to transform into a pupa. 



The following account of its metamorphosis is copied from the " American Ento- 

 mologist." 



After it first leaves the water, the larva crawls rapidly about, in the night-time, to 

 find a suitable place for its pupal transformation, usually selecting for this purpose the 

 under surface of a flat board or log, or burrowing under some large 



O 7 O O 



stone. In pursuit of this object they sometimes wander almost a 

 hundred feet from the water's edge, and we have known them to 

 crawl up the walls, and on to the roof of a low, one-story frame 

 building, and then tumble accidentally down the chimney, to the 

 great dismay of the good w r oman of the house. At this period of 

 their existence they are much sought after as fish-bait, having a 

 very tough integument, so that one larva suffices to catch several 

 fish ; and they are called by fishermen " crawlers," " dobsons," and 

 sometimes, we hope rarely, " hellgrammites." They can pinch pretty 

 sharply with their strong jaws, though not sufficiently hard to draw 

 blood ; and they also use the processes at their tails as prehensile 

 organs to aid them in climbing. 



"After it has selected a suitable hiding place, the larva forms 

 FlG ' 2 l 7 siaiid arva f a ru( ^ e ce ^ m tne earth, within which it transforms into an inactive 

 pupa, with no mouth to receive food, and no anus to discharge fasces. 

 It usually leaves the water about the beginning of June, and by the end of that month, 

 or the fore part of July, the winged fly bursts from the shell of the pupa." 



A smaller form, though still a large insect and an interesting one, is the Chauliocles ; 

 it chiefly differs from the foregoing genus in its beautifully pectinated, or feathei-ed 

 feelers, and its more delicate wings. Such is Chauliodis pectinicornis, our commonest 

 species. The larva of another species ( C. nastricornis) is like the hellgrammite, but 

 considerably smaller, and with no caudal filaments; while the last pair of spiracles 

 is on the tips of a pair of contractile filaments. 



The genus Sialis, which gives its name to the family, comprises a few small spe- 

 cies, which inhabit the Old and New Worlds, while the singular genus Raphldia, so 

 far from being aquatic, lives under the bark of trees, where it pursues small insects ; 

 the species in this country are confined to the Pacific States. 



The lace-winged flies, which form the family HEMEEOBID^:, are characterized by a 

 slender body, a small, square prothorax, and net-veined wings, while the lame, which 



