8 



HARDWICKE' S SCIENCE-GOSSIP. 



in curious rhythmic cadence. Two or three branch- 

 ing veins will have the central portion hurrying 

 forwards, it may be towards the right of the observer, 

 then suddenly they may be arrested in their course, 

 and return towards the direction from which they 

 came. As, however, this description can only apply 

 to the small portion visible at once in the field of a 

 microscope, it would be presumptuous to imply that 

 this would adequately describe the movements in the 

 whole mass. 



Jas. Saunders. 



Luton. 



(To be continued.) 



THE PERIODICAL APPEARANCE OF 

 EDUSA. 



WITH regard to the question now in debate as 

 to whether the abundance of Edusa last 

 autumn was, or was not, to be attributed to the immi- 

 gration of their parents in the early summer, may I 

 state the following facts ? 



1. That there were, I am certain, no Edusas to be 

 found on the downs near here at any time during the 

 years 1890 and 1891. 



2. That in June last I saw them here and there all 

 over the downs. 



3. That all the specimens seen by me appeared to 

 be more or less worn. I caught several, and these 

 certainly were all worn. 



4. That Edusa is a very active, compact, and, may 

 I say, muscular (?) insect, considering its expanse of 

 wing, and will fly for many hours untiringly, day 

 after day, and without showing any appreciable wear 

 and tear. 



5. That our summer migrant birds, soon after their 

 arrival on our shores, spread rapidly over the country 

 in all directions. (If Edusa migrates, why should it 

 not do the same thing?) 



6. That butterflies do without doubt migrate. 

 I have myself witnessed the migration of tens of 

 thousands of Cardui, and Darwin records that once 

 when at sea he saw " clouds of Edusa," twelve miles 

 from any land ? 



7. That this insect abounds over most parts of the 

 continent, and, in view of statement 4, could easily 

 reach this country from France in three or four hours. 



8. That even a strong wind, unless it were a 

 regular gale, would not, in all probability, much 

 retard, and certainly would not altogether prevent, 

 the immigration of Edusa, if and when the impulse 

 seized it; for Miss Gordon Cumming, in "Two 

 Happy Years in Ceylon," speaks of an annual 

 migration there of " countless myriads " of butterflies, 

 which, she says, " travel like an ever-flowing stream, 

 against the wind, at the rate of about ten miles an 

 hour." 



9. That all the above statements may be applied 

 to Cardui, except that this species was (here at any 



rate) less plentiful in the autumn — a very singular 

 and, to me, inexplicable fact. 



The migratory impulse seems this year to have 

 acted simultaneously on Edusa, Hyale, Cardui, and 

 the beautiful D. Pulchella— a remarkable fact, and 

 one that presents a tough nut yet to be cracked by 

 naturalists. The strange thing is the spasmodic and 

 apparently capricious action of the migratory instinct 

 in these insects. 



R. B. POSTANS. 



Eastbourne. 



A FUNGUS GROWING ON TEREBENE 

 SOAP. 



By R. L. Maddox, M.D., Hon. Fell. R.M.S. 



ON uncovering a bar of Terebene soap, which 

 had been wrapped in paper and left on a shelf 

 in the cellar for a couple of years, it was found to 

 be closely covered on all sides with what looked like 

 spots of soot, or light coal dust, to the naked eye, 

 the spots being mostly circular and raised, ranging 

 in diameter from the xgth (one sixteenth) to the 

 rj^jyth of an inch, or even less. Examination with a 

 lens showed these spots to consist of a minute fungus, 

 of which the following may be taken as a fair 

 description when seen under the microscope, and 

 after sectioning and mounting in a mixture of gly- 

 cerine and potassic acetate. 



As seen hi sitii, the large and small black spots 

 are found to be composed of a crowd of spores closely 

 applied, and piled up on each other, the edges 

 showing here and there free conidia, with adherent 

 spores, projecting only a short way from the little 

 mass, and with scarcely any hyphx supporting them 

 beyond a somewhat longish cell or two. Some of 

 the conidia appear to have bent over, or to have 

 other spores attached to them, forming a small 

 irregular cluster. 



The spores, both free, and those lying together, rest 

 on a fine compact mycelium of a brownish colour, 

 and vary both in size, contour, and colour. The 

 shape being either oval or round, and the colour of 

 a dark brownish olive green, there being also a few 

 rather reddish brown in tint. The very fine spots 

 look like a blackish dust to the naked eye, and con- 

 sist of only a few spores, 'adherent and starting into 

 growth. The mycelium threads, when they can be 

 disentangled, consist of very fine thread-like tubes, 

 with here and there specks of a granular plasm ; 

 some of the threads swell out into pale globular 

 cells, and, apparently lying free, are rather large 

 yellowish cells. Some of these are also attached to 

 the end of the growing part, and are occasionally 

 divided into two parts by two fine lines. Many 

 of the old spots are exceedingly brittle, and under 

 no method could I obtain a thin section ; but, by 

 keeping some thick shavings from the outside of the 



