426 Mr. Newport on the Anatomy and 



but imperfectly preserved in the dried insect, and consequently most easily 

 overlooked, exist in all the specimens of the different species oi Pteronarcys va. 

 that collection. Branchiae were thus found to be normal structures in the 

 imago Pteronarcys, and even to characterize the genus, although they had 

 hitherto entirely escaped observation. 



Since the period when I obtained my single specimen, in December 1843, I 

 have anxiously awaited the receipt of other examples of the insect preserved 

 for dissection ; but as I have not yet been so fortunate as to obtain them, and 

 as I desire to make known some account of the internal structures of this re- 

 markable insect, I have now made an anatomical examination of my speci- 

 men, having taken especial care to preserve it as entire as possible, in illus- 

 tration of the facts of its anatomy, and in authentication of my account of 

 them. 



M. Pictet, the most diligent and elaborate of all monographers of the Neu- 

 roptera, has j-egarded the insects of the genus Pteronarcys, Newm.*, as only 

 large Perlidcef, which have the body strong and elongated, and the wings 

 large and supported by numerous and solid reticulations. He has, however, 

 very properly, retained the genus as established by Mr. Newman on the struc- 

 ture of the wings. But the entire organization of Pteronarcys, — not merely 

 those portions of its external anatomy, the branchiae, which were unknown 

 to that gentleman when he established the genus, but also the whole of its in- 

 ternal conformation, — most fully authorise the separation of Pteronarcys from 

 Perla. The peculiarities of the structures I am about to describe prove 

 the correctness of view, and the acuteness of zoological perception and tact, 

 which led the naturalist just mentioned, although entirely unacquainted with 

 the anatomy of some of the primary and really important organs of the insect, 

 — the peculiarities of which, doubtless, are of first importance in the life and 

 habits of the species, — to establish his genus on characters which then were 

 the most obvious for zoological description, although of only secondary phy- 

 siological consequence, — the reticulations of the wings. 



To understand rightly the nature of the peculiarities of this insect, I must 



* Entomological Magazine, vol. v. p. 175. 



t Histoire naturelle gdndrale et particulifere des Insectes Neuroptferes. Premiere Monographic, 

 Famille des Perlides. Genfeve, 1841, p. 126. 



