498 THE SO-CALLED BUGONTA OF THE ANCIENTS. 



paper is made; when this pulp is beaten for the manufacture of paper 

 the larva although badly struck by the hammers, is not crushed, but 

 survives and i^roduces a Hy. This fact would seem incredible, if it was 

 not afiBrmed by the great naturalist." 



This tenacity may have been the cause of the success of this fly in 

 the so-called struggle for existence. It has attained an almost univer- 

 sal distribution, and the progress of civilization has only increased its 

 opportunities. In ancient times it had to look out for stray carcasses; 

 civilization offers it its drains, canalizations, cesspools, and dung-heaps, 

 in which it can wallow in abundance, and perhaps better i)rotected 

 against possible enemies. Different in this from other kinds of insects, 

 which disappear with the culture of tlie land, E. tenax thus gained a 

 new impulse, and spread in new countries with an astounding rapidity. 

 It entered into a kindof commensalism with man, like the.!/ ?/-s'(Y/^/o»/es- 

 tica, Teichomyza fusca, and some other dipterous insects, Avliich are at 

 present hardly found anywhere except among human habitations. It 

 is very rare now to come across a carcass, and to see U. tenax hovering 

 about it. The only instance I have found in the literature consulted 

 by me concerns another species of Eristalis, E. anthophorinus Zett., 

 and that case occurred in a distant and primitive country. Zetter- 

 stedt {Dipt. Scand. ii, 666), being in Lapland, observed a small swarm 

 of flies of this species round the carcass of a sheep: " Ad cadaver ovis 

 putridissium, aquai stagnanti maximam partem immersum, odore fceti- 

 dissimum, individua 7 vel 8 souopipiente celerrime circumvolandocon- 

 gregautia, et in cadaveris parte supra aquam elevata interdum seden- 

 tia, die 16 Junii in Lapponia observavi, ova in cadavere sine dubio 

 depositura."* 



The occurrence of this fly is reported from all parts of the Old World 

 with the exception of South Africa and the East Indies, about which 

 1 have no certain data. It occurs in the whole of Europe, as far north 

 as Lapland, the northern and central Asia, beginning with Syria and 

 Persia, through China to Japan ; in northern Africa (Algiers) and on 

 the islands surrounding Africa (Madeira, the Canary Islands, and, on 

 the eastern side, Madagascar and Bourbon). During my twenty years 

 of residence in North America, spent in collecting diptera and receiv- 

 ing collections from many other entomologists, I never met with a spec- 

 imen of E. tenax until I^Tovember 5, 1875, when, to my great astonish 

 ment, I found one on a window in Dr. Hagen's house in Cambridge, 

 Mass. A year later (October-November, 1876) I observed several 

 specimens on the fences of Newport, R. 1. In June, 1877, I sailed for 

 Europe, but I heard afterwards that during the same year the fly had 



* (Translation). In LapLand, on the 16tli of June, near a very putrid carcass of a 

 sheep, the gi'eater part of which was immersed in stagnant, most offensively smell- 

 ing water, I perceived seven or eight specimens flying about rajiidly and emitting a 

 piping sound, and sometimes alighting on the portion of the carcass above the water, 

 evidently for the purpose of depositing their eggs. 



