3° 



HARDWICKE'S SCIENCE-GOSSIP. 



ON COLLECTING DIPTERA. 

 By E. Brunetti. — No. II. 



[Continued from p. 12.] 



SO far as the actual collecting of specimens goes, 

 to which I wish to confine myself here, the 

 rules to be observed are few and easily fulfilled. 



Diptera may be caught with the ordinary gauze 

 butterfly net — one that is rather shorter than usual 

 will be found most useful, as many flies persistently 

 hover above bushes and the small recesses in the 

 lower branches of overhanging trees, and a long net 

 is liable to get entangled in the brambles or other 

 prickly vegetable growths, that is often met with in 

 such situations. 



Most of the Diptera inhabiting these situations are 

 partial to a sho t flight, or to running about the 

 sunny foliage, and when disturbed often return to 

 the spot again, or retreat to the interior of the wood. 

 Such are many of the Syrphidae, the Dexiidae, 

 Tachinidae, Asilidae, and many of the Tipulidae. 



I must here diverge for a moment to remark, that 

 many families or groups have a special manner of 

 taking flight, and the sooner the collector becomes 

 acquainted with the peculiarity of each, the more 

 successful will he be, for a second stroke of the net 

 is rarely afforded one in the case of flies, owing to 

 their swift flight. 



Bushy banks, especially those on which various 

 wild flowers grow, are good hunting grounds for 

 Diptera, and the species in these situations will all 

 be found to take rapid flight, seldom returning to 

 their resting place, unless they belong to the Syrphidae, 

 a family noted for hovering over flowers, especially 

 during sunshine. 



As a rule, the species preferring hot and sunshiny 

 days for flight are more richly coloured and are more 

 rapid on the wing than those which are to be found 

 at all times in greater or less abundance. 



The Syrphidae, a few genera of the Stratiomyiidse, 

 are the groups principally affected by the heat, and 

 most likely to disappear with the sunshine. 



Some species irequent fields where cattle graze, 

 and the neighbouring woods, such as the Tabanidae, 

 Oestridae, any many genera of blood-sucking Muscidae ; 

 for these groups it is almost useless to search beyond 

 the favoured localities. 



One family, the Tipulidae proper, is most plentiful 

 on the borders of pools, marshy banks, and bushes 

 growing, so to speak, in detached patches on large open 

 spaces, though these latter should be sheltered in some 

 manner, either by isolated groups of trees, the borders 

 of a wood, or by being situated in a natural depression 

 of the ground. After an evening shower this family 

 is often abundant in such localities ; I have often 

 taken dozens on such occasions, where during the 

 daytime it was difficult to beat a specimen from the 

 bushes. 



Many species are only to be found on dung, 

 though in comparative abundance there ; most of 

 these thus taken will prove to be acalypterate Muscidae, 

 the chief genera being Drosophila, Pula, Limosura, 

 Borbores, Tetanocera and Scatophaga (two species of 

 the last genus are abundant everywhere). 



One brilliantly coloured genus of the higher 

 Muscidae, Lucilia, is often attracted by the odour of 

 excrementitious matter, and I have occasionally taken 

 Asilidae on it. 



The Limnobne and some other genera of Tipulidae, 

 the Culicidae and Chironomidae, chiefly frequent the 

 banks of ditches or ponds, owing to the larva being 

 aquatic, many species of these families are abundant 

 on summer evenings, often unpleasantly so, usually 

 collecting in small swarms and hovering over the 

 waterside or beneath the lower branches of trees. 

 Such are Culex, Limnobia, Trichocera, Chironomus, 

 &c. 



On reeds and the plants on the banks of ditches 

 may be taken the pretty genus of Tipulidae, Pty- 

 chopteryx. 



Human habitations form the habit of no incon- 

 siderable number of species, chiefly belonging to the 

 Anthomyiidae, a large sub-family of Muscidae, over 

 two hundred species of which are known to be 

 British. 



The Phoridae, a small family following the acalyp- 

 terate Muscidae, are, I believe, more often taken in 

 houses than elsewhere. 



I could probably compile a list of over fifty species 

 taken myself in London houses, and Mr. Verrall, I 

 believe, can increase this number to over seventy, but, 

 in his case, though living in a country town, a more 

 extensive range of species might naturally be ex- 

 pected. 



Sweeping is a most excellent means of obtaining 

 the smaller species of Diptera, and should be ex- 

 tensively employed, whilst beating is equally pro- 

 ductive ; both these methods should be practised at 

 every opportunity. 



I think I have now given a sufficient number of 

 hints respecting the nature of localities likely to 

 produce Diptera, and will conclude this part of the 

 subject, by saying that, as a general, universal rule, 

 Diptera are to be found everywhere and at all times. 



Respecting setting, I must now make a few remarks, 

 though the rules observed in the other orders of 

 insects are applicable to the Diptera also. 



It is better to pin all the specimens, but should 

 any be carded, it is advisable to invert one or more 

 of them, after subjecting them to a close examination, 

 even to the minutest detail, so that no doubt can 

 possibly exist of being the same species. 



My experience teaches me, however, that in all 

 cases, carding is better avoided, and the delicate pins 

 now manufactured abolish the necessity of this 

 questionable method of preserving Diptera. 



When these extremely fine pins are employed, they 



