HARD WICKE'S SCIENCE-G OSSIF. 



35 



known by the Arabs as Bedegar. This thistle, or 

 certain portions of it, entered the ancient pharmaco- 

 pseia or medicine list, then was carried to Greece, 

 Italy, Germany and England where the name was 

 still retained, along with its equivalent in the 

 languages of those lands, as Akantha, Spina, Distel or 

 Thistle. In course of time, however, the term was 

 appropriated (about the fifteenth or sixteenth century) 

 to another article, viz, an insect gall, and thus in the 

 end the spongy balls on the wild rose came to be 

 regularly known under the Arabic name of Bedegar, 

 or the little stabber. 

 Idle, Bradford. 



AN INTRODUCTION TO THE STUDY OF 

 BRITISH DIPTERA. 



By E. Brunetti. 



I. INTRODUCTION. 



T T will be my endeavour in the following papers to 

 -*■ give an outline of the British Diptera. 



Twenty years ago, but little was known respecting 

 this order, but the labours of Messrs. Verrall, Meade, 

 Dale (and, in a lesser degree, other entomologists), 

 have resulted in rich collections of these insects, 

 and with the material at present available, we may 

 venture to speak with some approach to accuracy of 

 the species of Diptera indigenous to the British 

 Islands. 



Mr. Verrall's recently-published list {1888) forms a 

 splendid foundation for our researches, and the 

 student, I trust, will find the following remarks of 

 assistance to him during his preliminary investiga- 

 tions and first collecting excursions. 



On the Continent the Diptera are tolerably well 

 known and the fact of our knowledge of the British 

 species being so unsatisfactory should be a greater 

 incentive to the true entomologist, as the order offers 

 far more opportunities of rendering real service to 

 science than do either the Lepidoptera or Coleoptera. 

 It is true that students have few incentives to take 

 up the study of the Diptera, as the disadvantages are 

 so numerous ; collections being few and far between, 

 and usually the property of private individuals. The 

 national collection of these insects is in a highly 

 unsatisfactory state, for the very simple reason that 

 no one has been employed to bring it anywhere near 

 up to date ; to correct the numerous and most 

 palpable blunders in nomenclature ; to fill up any of 

 the large gaps made by the absence of whole genera, 

 as well as numbers of the most common species ; or 

 to replace by fresh specimens the old damaged and 

 dirty ones that do duty as the National British 

 Collection. 



Although collections available for reference, and 

 books are so scarce, there are now fortunately 

 several workers at this group who are fairly well 

 acquainted with the order, and who, as a rule, are 



very ready, leisure permitting, to assist beginners by 

 naming their captures ; I myself being most happy to 

 help collectors in this manner, provided the speci- 

 mens sent for identification be in good condition. 



1. COLLECTING. 

 Diptera, to put it shortly, may be captured in 

 every part of the country in tolerable abundance, in 

 almost every conceivable nature of habitat, dis- 

 appearing only during the very coldest weeks, and 

 even in mid-winter certain species (generally 

 Nematocera) may be obtained by those who know 

 where to look for them. 



The ordinary gauze butterfly net is most useful for 

 capturing them, and the sweeping net for those 

 inhabiting the borders of streams, dry ditches, long 

 grass, banks and other similar habitats. 



As most flies rise, when alarmed, with great 

 rapidity, a short quick stroke is necessary to capture 

 them, a second opportunity rarely being afforded. 

 It has been computed that certain species rise with a 

 velocity of twelve feet a second. 



As many groups and certain genera have a special 

 manner of their own of taking flight, and of behaving 

 when on the wing, it is of invaluable assistance when 

 the collector is able to recognise at sight the family 

 to which the intended capture belongs. 



In sweeping, much discretion and experience is 

 necessary, as the net rapidly fills with twigs, leaves, 

 larvae, beetles and spiders, these latter being the 

 bugbear of the collector whilst sweeping, as they 

 spin up the contents of the net (which I transfer 

 bodily into large chip boxes, to be sorted out at 

 home) into a tangled, unrecognisable mass, besides 

 devouring a large proportion of the Diptera captured. 

 Larger species have to be captured singly and 

 transferred to glass-top boxes, into each of which the 

 collector with a little manipulation and experience 

 should be able to place a dozen ; care being taken 

 to keep the carnivorous species separate (as Empis, 

 Leptis, &c.) or one finds on reaching home, perhaps, 

 every specimen more or less eaten. 



Species in which the legs are exceptionally brittle 

 and break off easily, should be given separate boxes, 

 if possible i^AnthoJuyidic, lipuUdic, Dolichopidce, <S:c.), 

 or at most only two or three specimens placed in 

 each box. 



Whenever the opportunity occurs, take a long 

 series of a species, as by this means varieties may be 

 obtained and the limits of specific variation fixed. 



If a note-book of captures is kept, it will be found 

 of invaluable assistance during subsequent seasons, 

 and this plan should be adopted by all who desire 

 doing anything of value towards completing our 

 knowledge of the order. 



3. PRESERVING. 



Diptera should invariably be brought home alive, 

 and killed by the fumes of burning sulphur. I am 



