326 Professor E. B. Poulton on 
Diptera. In this group very kind help has also been 
received in special cases from Mr. G. H. Verrall, Mr. J. E. 
Collin and Mr. E. E. Austen. In working out the 
Neuroptera kind assistance was received from Mr. W. J. 
Lucas, Mr. W. F. Kirby, Mr. Kenneth J. Morton and Mr. 
C. A. Briggs; the Orthoptera, by Seftor Don Ignacio 
Bolivar, Mr. W. F. Kirby and Mr. R. Shelford; the 
Lepidoptera, by Sir George F. Hampson, Dr. F. A. Dixey, 
Mr. J. Hartley Durrant and Mr. R. South ; the European 
and British Rhynchota, by Mr. Edward Saunders, F.R.S. ; 
the Rhynchota from other parts of the world, by Mr. W. L. 
Distant ; the Coleoptera, by Commander J.J. Walker, Mr. 
Guy A. K. Marshall, Mr. G. J. Arrow, Mr. C. J. Gahan, Mr. 
G. C. Champion, and Mr. W.. Holland. 
The Hymenoptera have been especially difficult. Mr. 
Edward Saunders, F.R.S., has determined the European and 
British Aculeates; Colonel C. T. Bingham, the Oriental 
and African Aculeates and Parasitica; Mr. Claude Morley, 
the European and British Parasitica; Rev. F. D. Morice, 
the European and British Tenthredimdx; Mr. A. J. Chitty 
devoted much time to the difficult problem presented by a 
minute Cynipid. 
A minute species of Collembola, which had puzzled 
many naturalists, was finally traced to its true position by 
Mr. Claude Morley. 
The British Spiders have been kindly studied by Mr. F. 
P. Smith, but the results of his labours are almost confined 
to the material for Part II. 
Special inquiries have been courteously answered by 
Mr. C. O. Waterhouse, Mr. G. T. Lyle, Mr. H. O. Forbes 
and Mr. W. R. Ogilvie-Grant, as well as by the naturalists 
whose names have been already mentioned. 
Numerous errors are so difficult to avoid in a memoir of 
this kind, dealing with such varied material and bristling 
with data, that exceptional time and trouble have been 
devoted to the correction of proofs. Not only have they 
been read several times by the writer, but the following 
friends have also most kindly been through them and 
made many corrections and valuable suggestions :—Mr. 
Edward Saunders, F.R.S8., Colonel J. W. Yerbury, Mr. G. 
H. Verrall, Mr. J. E. Collin, Mr. Claude Morley, Mr. G. A. 
K. Marshall, and Commander J. J. Walker. Mr. W. J. 
Lucas read through the proofs of the Neuroptera. Mr. 
Marshall also rendered the kindest assistance in bringing 
together upon a single copy the corrections on six sets of 
