THE AMERICAN ENTOMOLOGIST. 



139 



AV'e will now give such recorded cases as we 

 liiive been able to glean, of the occurrence of the 

 larvfE of Flat-flies or other Two-winged flies in 

 the human bowels, whether in this coQutry or 

 in Europe. In Europe there arc two species in 

 particular, respectin"' which such facts have been 

 recorded, namely, Iho Puppv Flat-lly {Horn, 

 canicularis. Mcig.) and llic Ladder-lly (lloin. 

 scalaris, Meig.) The larvse of the former arc 

 well known to occur normally in rotten vege- 

 tables and decayed cheese, and the fly itself, 

 from its being often noticed in houses, has been 

 sometimes called " The Lesser House-fly,'' 

 though from the true House-fly {Miisca domes- 

 tica) it difl[ers by very conspicuous structural 

 characters. The larva; of the Ladder Flat-fly 

 are met with in human excrements, and from 

 their being often found in the putrid contents 

 of privies, the fly itself has freijueutly been 

 characterized as "the Privy-fly." 



The ]{ev. L. Jenyns, of Cambridgeshire in 

 England, published SO or iO years ago a very 

 detailed account of the hxrviv of the Puppy Flat- 

 fly having been discharged from the intestines 

 of a clergymen.* Fallen records a similar case, 

 though he thought that the larva' might possibly 

 belong to an allied species. f On the other 

 hand, Westwood tells us that in two different 

 medical works, one in the German and the other 

 in the English language, the larvse of the Ladder 

 Flat-fly are stated to have been found in the 

 human body. J Several other European cases 

 are on record, where the larva; of Two-winged 

 flies have either been evacuated from the anus 

 or vomited from the mouth ; but in most of them 

 the genus to which they belonged cannot be 

 accurately determined. In the United States, 

 Dr. Leidy, as quoted by Dr. Packard, § has re- 



I'ortlieyarc ilescribeU as bt-ing siuiilai- to tlic lateral braiiclii:i', 



whereas in WilsoTii thev are mere tubercles. In one verv 



remarkable respect, however, LeMi/i ilillVrs both from Wii- 



soni and frcmi jinmintrii: li.r iii.^lcad nf llie ilursiil branchiie 



on the anal joint l.cinn' .~tiU lunjriv mm.I ^lei 



on the ijrecedin^' ubil()HaiKil.juiuts, iln-x arc 



"promincut tubercles," ami arc crnilicun 



spu'acles. Again, in tile arraii^^ciiicnt 'iftti 



pods, Leiffyi seems to agree with Mlhoni 



pruiiivora; for accordinj^ to the dcscripti 



segment lias the anterior row (■!■ papilla 



carina apparently being con^iikicd a^ a • 



the segment. As Dr. l.ciilj - .l.-iripia 



inaccessible to manv of onr i-iail.i-, wi' i 



in fidl :—" Larva 3-3* lines Imi-, l-i; line; 



elliptical, tlicarticnli stron;:lv inark.il, cv.rv 



shagreencd; bo.iv antciinih' -ul.aciilr. |,,,si. 



Head bipapillalc', with a iiairol h v- proii. 



month, .\rliculi liu-nishi.,| .loisallv and later 

 six lon^' postcriorlv dixcr'.'cnl ibxililc cid 



Ventral sci; nt- 'iran-vcVscIv siil.dix idcd. tlic p"-lcrior 



snbdivisi.iii lunn.sbcd wilh a' traiisv crsc row of papilhc. 

 Caudal arlicuUis ilorsally hli>pini;, furnished with a jiair of 

 prominent spiracular tubercles, and frini;eil with six spines. 

 Anus ventral.— Described from a specimens." (From Proc. 

 Ac. Xat. Sc. Philail. 1S.'0, Biolofiical ile|mrtment, page S.) 



h'rt 



r than those 



tail 



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d to be 

 msidei-f 



d as 



ath 



■ach \c 



with 

 Ural 



cai 



uitonii 



the 



siiIj 



li vision 



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1 is 



short, 



and 



I'll 



luce it 



here 



lUltclv 



un.l spi 



'Trans. London Entom, Soc, "N'ol 

 tQuoted Westw. Introil . II. p .-iTi 

 XIbid.\t. 571. 

 §GHidc to the Stud!/, &<i. 307. 



corded a case where numerous larva;, supposed 

 to be those of some Flower-fly (Anihomyia), 

 were given to him for examination by a phy- 

 siciiiu, Avho had obtained them from his own 

 person. This physician, it is added, had been 

 seized with all the symptoms of cholera morbus, 

 and in his discharges he had detected numerous 

 specimens of this, (o him, unknown parasite. 

 The above circumstances took place in the latter 

 part of summer, and it was suspected that the 

 larva; had been swallowed along with some cold 

 boiled vegetables. The very same kind of larva 

 had been previously observed by Dr. Leidy in 

 anolher such case, which was likewise accom- 

 panied by the ordinary phenomena of cholera 

 morbus. On referring to the description of 

 these larva; published by Dr. Leidy, we And 

 that they are represented as having very nearly 

 the same kind of lateral gills as those which we 

 have flgurcd above ; and they must consequently 

 appertain to the Flat-flies and not to the Flower- 

 flies {Anthomyia), as was erroneously supposed 

 by the author of the description. 



Of course, every one must perceive at once 

 that a larva furnished with gills, and not liable 

 to drown when immersed in fluid or semi-fluid 

 matter, would stand a much better chance to 

 live and flourish in the human stomach, than a 

 larva that breathes the air much in the same man- 

 ner as we ourselves do. But there is authentic 

 evidenco- that larva; which breathe through spi- 

 racles in the ordinary manuer, and not through 

 lateral gills, have been voided either upwards or 

 downwards from the human body. ForDr. Leidy 

 has further reported* a case where a number of 

 specimens, which appeared to be larva; of the 

 Blue-bottle Fly, were given him by a physician 

 as having been vomited from the stomach of a 

 child; and Baron Osten Sackcn has kindly in- 

 formed ns, that in the winter of 18G8-9 some 

 smooth Dipterous larvw were handed over to 

 him by a New York physician as having been 

 voided in the excrement of a child; and that 

 from one of them he reared what was apparently 

 a specimen of the common House-fly (Musca 

 domesHctt') . So far as we are aware, this is the 

 only case recorded by authors, where larvas dis- 

 charged from the human body have been actually 

 bred to the perfect Fly stale. 



The question naturally recurs here — "How 

 in all these numerous instances did so many 

 larvas And their way into the human body?" 

 Two opinion.?, as the reader will have noticed, 

 have been expressed above as to this knotty 

 problem ; one by Dr. Lady's fr'.end, that all the 



'Proc. Ac. Nat. Sc. Philad., IX>'J, Biological Deiiarlment, 



