1873.] 281 [Hagen. 
9. Psocus pusillus Harris’ Corresp., p. 331. 
There is no such species in the collection nor in the catalogue. 
Harris’ Catalogue includes fifteen numbers for the Corrodentia 
(represented by thirty-nine specimens), only one, No. 70, wanting, 
but most of the others are only fragments. ‘The Psocus described by 
him and published in his Correspondence are all to be identified by 
the types, except Psocus quadrifasciatus and the missing Psocus pu- 
sillus. 
PERLINA. 
1. Pteronareys Proteus Newm. Entom. Mag., vol. v., 177, 
3. (Not Hagen.) 
No. 118. Perla generosa Harr. (Pteronarcys Newm.). Maine, Ran- 
dall, 1836. ) 
There are in the collection two specimens, one, a half destroyed 
male with the end of the abdomen just in condition to prove the 
identity with Mr. Newman’s type in the British Museum, the orhen 
only parts of the wings. 
The species of the genus Pteronarcys, all but one belonging to the ~ 
North American fauna, are somewhat difficult to recognize. As the 
authors describing them, viz., D. Newman, Burmeister, Pictet, 
Walker, Newport, and Gosse, had, in every case, but few specimens 
before them, and as the real specific characters are only given for a 
few species, and often for but one sex, it is easily understood that they 
cannot be rightly determined by succeeding students. When I made 
the synopsis of the North Ameriean species, I had before me types 
of Walker’s species, given to me by the British Museum. But as 
some of them, as I found in a later visit to London, do not belong to 
Mr. Newman’s species, as I supposed before, I was misled, and made 
some errors in the diagnosis of the species. Now the material before 
me is more extensive, at least for some species, and it will perhaps 
be convenient to give here a short notice of the species belonging to 
this interesting genus, especially as just the species represented in 
the Harris collection has been the starting point of most of the con- 
fusion. 
Prreronarcys Newm. 
I. Pteronarcys Proteus Newm., |. c. 
The British Museum possesses the types described by Mr. New- 
man. There are two males (agreeing in the formation of the last 
