PREFACE TO THE FIRST SERIES ix 



dry place, free from accidental jars and careless handling. Naphthalin 

 wrapped in a piece of net should be pinned in a corner of the box as 

 a guard against mites, the great enemy of the dipterist as of the 

 entomologist in general. 



The chief season for collecting in this country is from March till 

 October, the sunny forenoon being the best time. Windy days are 

 very unproductive. Even well-known and good localities are sometimes 

 a blank, from causes we do not know, for flies seem very capricious in 

 their habits. But, like other creatures, they have special haunts where 

 they may usually be found at the proper season, and where they may 

 be expected to occur if carefully searched for. Considerable experience 

 in their habits and localities is needed by the collector. Generally 

 speaking, umbelliferous plants, also bramble, hawthorn and ivy bloom 

 seem to be most attractive. Flies often settle upon gate-posts, railings, 

 and tree-trunks, especially if wounded or decayed. Others frequent 

 salt-marshes and swamps, ponds and river-sides ; whilst heath-lands, 

 sheepruns, bare hot sandy areas and commons attract others. Horse 

 and cattle droppings and decomposing animal and vegetable matter 

 are well-known baits for many species. Others attack living animals, 

 not excepting man ; and certain flies prey on insects and spiders. 

 Should horses or cattle be approached for the purpose of taking flies, 

 much care must be exercised, as a net will generally stampede them ; 

 it is difficult to employ it to advantage under such conditions. 



This little book has received the kind encouragement of many 

 entomologists, among whom I may mention Professor Nuttall and 

 Mr Warburton, both of Cambridge. Much practical help in the 

 selection of species, and information as to types selected and their 

 larvae, has been afforded by the kindness of Professor Theobald, whose 

 assistance, it is hoped, has added greatly to the utility of this book. 

 Thanks are also due to Mr Harwood, of Colchester, for the fine speci- 

 mens of diptera which he has furnished for the photographs herewith 

 presented. It has not always been possible to do them justice, owing 

 to the difficulties previously noted as besetting the photographer. 

 Mr H. Waddington kindly supplied some fine microscopic slides. 

 The author's brother, Mr N. D. F. Pearce, has also helped with the 

 illustrations, as to the success of which the reader must be left to 

 judge. Acknowledgement has been made in every case, it is thought, 

 where help has been received : and if this effort is successful it is 

 hoped that it may be some day supplemented by a further series of 

 pictures, to fill a few gaps that were unavoidable in the present volume. 



