ENTOMOLOGIST AND BOTANIST. 



231 



by a vciy short interval ; ncai- the tip of the ab- 

 domen there is a row of still more minute sjiincs. 



I did not sec the exclusion of the perfect in- 

 sect ; but, according to Vcnlat, after 13 — 14 days 

 spent in the pupa state, the thorax splits and the 

 fly escapes, wrapped in an air-ball, which makes 

 it rise rapidly to the surface of the water ; during- 

 this interval, the limbs remain folded as in the 

 pupa ; but as soon as it reaches the surface, the 

 limbs unfold tliemselvcs in an instant and the 

 fly walks on the water towards the next stalk, 

 where it remains until its wings have become 

 sufficiently hardened. 



Tlie imago of S. rcptans has acquired in Eu- 

 rope, under the name of ''the gnat of Columljatz," 

 a reputation ec[ual to that of Glosdna morsUans, 

 the African T'/.iivjk. Immense clouds of this 

 bloodthirsty gnat infest the banks of the Danube 

 on the Hungarian as well as on the Servian side, 

 where the castle of the Cohimbatz is situated. 

 Their numbers arc such that animals attacked 

 by them seldom escape death, as they not only 

 cover the skin, but penetrate in every orifice, 

 even the lungs, and produ<'e the most intolerable 

 inflammation. More than six hundred head of 

 cattle were destroyed in tliat region in the single 

 year of 178;!. The same gnats are mentioned in 

 Poland as far back as 167!i, wlicrc, according to 

 the (i)robabl\- exaggerated) accounts of the time, 

 thirty men were killed by them. In the Northern 

 States and Canada, Simulium is known under 

 ,the name of Black-fly, .and is, in some regions, 

 very amioying. In the West, it is called Buffalo *■ 

 i/nat, and I have heard of a case of destruction, 

 caused by them to mules at Vicksbiirg, whi<'h 

 fully equals that of Columbatz. 

 AUTHORITIES. 



KlonnORN — JVaturfffKch. J. Kleiiuteii Wasserlhlere. 

 Danzig, 1774. Tali. VTl. Contains, according to a 

 statement in Tlion's Arcliiv, A nl. II, a rough figiu'c of 

 the larva. 



Otto Fabkicius— Scliril't. (1. Gcsellsch. il. natiirf 

 Freiinde in Benin, Vol. V, p. ■i'54-259. (nS4.) Tlic 

 article is entitled "Hpscln-eibung d. Atlas-mticUe iind 

 ilirer Puppe," ami contains a nuiglifiunn' olthc iiupa. 

 its poncli, and of tlio pcrlei-t insect. The lai-\ a was not 

 known to Fabricius. 



Veupat — Jleni. pour scrvir ."i l"hi.stoirc dcs Simulies, 

 prcsente i la Soc. d'liist. natur. do BiVlo en 1821. In 

 ^aturw. An/,, dor .Schweizei-. (icsellsoh ; 1S2.", Vol. V, 

 p. (i5, translated in German in Tliim's Archiv, II, 2, pp. 

 66-<i9, with figures. This is the principal paper on the 

 subject; the figures are very good; they are reproduced 

 on areduced scale iu WeHw. Jntrod., if, fig. Vlii, II), 20. 

 Although Verdat calls the species i>. sericeum, {syn. 

 reptans), I am inclined to think that it is S. omatum. 



Fkibs — Monogr. Simul. Suea'ce (in Dissert. Academica: 

 "Obscrvationes entomologicas"). Pars I, fig. 6-7 (1. p.), 

 1824. Translated (without figures) in Meigen, Euri>p. 

 ZweiH. VI, p. 30!l. Some disercpaneics lietween Fries" 

 and Verdafs account ha\(' been adverted to above. 

 Meigen's extract is evidently wrong in stating that the 

 larva lives in instead ol'o» the stalks ofplantsT 



Planchon — Hislulre d'une lane aouaiujue dii Genre 

 Simulium; Montpellier, 1844, Keproductiou of already 

 known fticts, with some new details, and especially some 



remarks on the anatomy of the larva. No plates. S. 

 rimlaiis, n. sp. 



Kollar — llenrthdhinij lUs von Th\ Medmics an die 

 Serhische liefjifninij ersfattttefi Berichtes ilh. die ^nfste- 

 hung und ]','rtilifiiii,/ ,!, r Cnltrmhalzer JUiivhti. (Sitzungs- 

 bcs. d. AVien. Acad., 1S4S; with three plates). Medo- 

 viez's report eontainccl many errors; for instance he 

 mistook another lar\a for that of Sim-iliuin. Kollar 

 corrects these ciTors, but otherwise gives notliing new, 

 except the ligure of the larva, which is drawn on a 

 large scale from nature. The Hgiiro of the pupa is bor- 

 rowed from Verdat. 



SCIIEI'-FER— In Rossi's Diptera Ausii-iaca, p. 14 (I84S). 

 ■S'. repiarts (xcrii-eiim). Short note; nothing tiew. 



AVestwood— (Jardcner's Chronicle, 1848, p. 204 (with 

 figures). Extract from tlie Ibrmer authors; (igiU'es 

 copied from \'erilat, on a reduced scale. 



KoLLlKER — Obscrvationes dc prima inscetoruni gen- 

 esi. Turici, 1842. Dissert, inaug. Embryological re- 

 searches on the development of the larva in tlic egg. 

 (S. eanescenn, Brcmi, n. sp.) 



1!LA(JK KNOT. 



It was long ago shown in the Practical Ento- 

 mologist by Mr. AValsh, that the Fungoid dis- 

 ease known under the name of " Itlack Knot" 

 to infest the cultivated Cherry, was quite distinct 

 from the disease of the same name which attacks 

 the cultivated Plum ; ;ind that the former most 

 probably took its origin from the wild C!hoke 

 Cherry {Cerasus virgiiilana), and the latter 

 from the common wild Plum (Pritnus amcri- 

 cana). Hence there followed the important 

 practical consequence, that Black Knot couM 

 not spread from Cherry on to Plum or from 

 Plum on to Ciicrry ; each parasitic fungus (-on- 

 fining itself to its appropriate tree. 



In -July, 1800, we were favored by Mr. B. 

 N. McKinslry, nurseryman, of East Sumner, 

 Kankakee county, Illinois, with .specimens of 

 Black Knot growing (|nitc ;ibundaiitly with 

 him, as he says, upon the Miner I'lum, but 

 not on any other cultivated plum. A single 

 glance sufih-esto show that this diseased growth 

 is essentially distinct from the common Black 

 Knot of the Plum, although like this last it is 

 evidently of fungoid origin In fact, both in 

 color, iu external texture, and in internal or- 

 ganization the two difl'cr so widely, that "Brown 

 Knot" would be afar more appropriate n,ame 

 than "Black 1-v.not " for the aflection oX the 

 Miner Plum. 



As the ^Sliiier Plum is a cultivated variety of 

 the Chickasaw Pluin (Prunus chicasa), it would 

 seem to follow that there arc three distinct 

 Black Knots, originating respectively from 

 Choke Cherry, from the common Wild Plum 

 and from the Chic^kas.aw Plum ; and furtlicr, that 

 tlic first is confined among our cultivated fruits 

 to Cherry, the second to our common tame 

 plums, and the third to the Miner Plum. It is 

 very remarkable that in Europe they have no 

 Black Knot at .all, whether upon Cherry or Plum. 



