Marshall. — On Neio Zealand Diptera. 217 



have them named. On mentioning this to Captain Hutton 

 he pointed out the disadvantages of having them named in 

 Europe, and advised me to work them up myself. Tliis task 

 I have found even more difficult than I anticipated, and my 

 comparative inexperience in the distinguishing and description 

 of specific characters is the only apology for the inaccuracies 

 and blunders that I must necessarily make in the following 

 classification and description of those Diptera that I have 

 been able to obtain. I intend to publish from time to time 

 papers on the various families of Diptera. These I hope to 

 supplement every year by species that have been discovered 

 during the preceding year ; so that, ultimately, these papers 

 may perhaps attain to the completeness of monographs on the 

 different families of Diptera. 



The classification I have adopted is that used by Mr. F, A. A. 

 Skuse in his papers on the Australian Diptera. These papers 

 have in every case been the model to which I have en- 

 deavoured to attain, and I must here express my keen 

 appreciation of the work he has done in collating and system- 

 atizing the writings and classifications of other dipterologists 

 in Europe and elsewhere. He has certainly very greatly 

 lightened the task of all subsequent workers at the Diptera in 

 the Australasian Colonies. He has kindly assisted me in all 

 cases where there seemed to me a doubtful issue, and has 

 offered to afford me every assistance in his power. Many 

 pages of these papers, more especially those that deal with 

 the descriptions and classifications of the families and genera, 

 have been taken almost directly from his papers, and he has 

 generously acquiesced in this wholesale cribbing. 



As far as possible, every genus will have a type-species 

 illustrated by a diagram, giving a general idea of the appear- 

 ance of the insect, and displaying those characteristics that 

 are made use of in the classification of the particular group to 

 which the insect belongs. In general these diagrams have 

 been drawn from dried specimens, and do not, therefore, give 

 with any exactitude the form of the abdomen and other soft 

 parts that are liable to shrinkage during the progress of dry- 

 ing. For specific characters the diagrams, though drawn with 

 considerable care, cannot always be trusted. It would, per- 

 haps, have been better to have omitted drawing the body of 

 the insect, and to have given diagrams illustrating the neura- 

 tion of the wings alone, as done by Mr. Skuse ; but my work 

 has already shown how useful such diagrams may be if made 

 use of with proper caution. 



I very deeply regret that I am at present unacquainted 

 with the life-history of any but a very few of the species that 

 I shall describe. I shall be able, however, to give diagrams 

 illustrating the life-history of what are, I hope, fairly typical 



