2 Rey. A. H. Eaton’s Monograph 
Structure has not hitherto received sufficient considera- 
tion in descriptive publications; which makes it necessary 
to examine all authentic specimens of described Hpheme- 
ride extant in collections, before the synonymy of the 
known species can be settled. With a view to reform, 
I have examined the undermentioned collections. Lists 
of the type specimens in each are given under the titles 
of the works in which they were originally described. 
Should I have opportunity, I will notice the contents of 
the principal French and German collections in some 
future part of my work. 
Through the kindness of Dr. Gray, I had unlimited 
access to the collections in the British Museum, com- 
prising Stephens’ collection (see Steph. 1835-6), Mr. 
Wollaston’s collection (see Hag. 1865), and the general 
collection of Newroptera (see Walk. 1853 and 1858-9). 
At the Linnean Society’s Library I examined the col- 
lection of Linné (see Lin. 1746). 
Mr. R. M’Lachlan has given me every assistance, by 
placing in my hands his valuable foreign collection 
(M’Lach. 1868, HEtn. 1871), and his British collection 
(Etn. 1870), and making them to all mtents my own. 
Through the hospitality of Mr. J. C. Dale, I had the 
pleasure of spending several days in gathering informa- 
tion concerning the geographical range of species in 
his British collection, and in describing the rarities in 
his foreign collection (see Htn. 1871). 
In the Museum at Oxford, with the permission of 
Professor Westwood, I inspected the University’s general 
collection (Htn. 1871), Prof. Westwood’s collection( Westw. 
1840), and Mr. A. Ronalds’ collection (Ron. 1836). 
The cabinets of my own University contain no remark- 
able Hphemeride. 
Some Australian species, sent by Professor M’Coy, of 
Melbourne, to Mr. F. Walker, were forwarded to me (Htn. 
1871) ; and Mr. P. C. Wormald obliged me with the 
loan of his collection. 
At Geneva, M. A. E. Pictet very kindly submitted to 
me the remains of Professor J. F. Pictet’s collection 
(Pict. 1848-5), and some Spanish Hphemeride which he 
had himself collected (Ed, Pict. 1865). 
M. de Selys-Longchamps’ collection, containing valu- 
able type specimens, was sent to me (see Lat. 1805; 
Guer. 1829-43; Ramb. 1842; Hag. 1858-9, 1861, 1864; 
Hin. 1871). 
