26 
FOREIGN MICROSCOPY. 
Chrysalis Mimicry. — A species of butterfly in Venezuela observed 
by Gollmer (Aidos amanda) makes a cocoon wliich it fastens to a 
twig, and which has the appearance of round holes. It is composed 
of two layers, of which the outer one is perforated, and the inner one 
so bent in as to leave a hollow space between the two. The chrysalis 
is protected by the strong inner layer which is not seen from out- 
side, and the outer layer aj^pears bored right through, and looks like 
the hole left by a species of wasp when it emerges from the pupa 
state.* 
Diatom Desiccation and Devival. — The ‘Journal de Micrographie ’ 
for December, 1877, gives a paper on this subject by Paul Petit, who 
states that after vainly searching amongst dried mud containing 
diatoms for spores or zygosj)ores, he made the following exiieriments : — 
He collected at various times of the year diatoms with their sub- 
stratum of mud, and allowed them to dry in the sun, sheltered from 
dust ; some for six, some for eight months. Last September he 
examined fragments from these deposits, and found the frustules 
transparent and seeming empty ; but a careful investigation showed 
that in the interior of a considerable number there were some large 
brown granules, which he took for desiccated endochrome. The vessels 
containing them were then filled with distilled water that had been 
well aerated, and exposed to direct light and heat of the sun. For the 
first three days little change was noticed, but from the fourth day the 
brown granules augmented in volume and assumed the yellowish tint 
characteristic of diatom endochrome. Watching from day to day the 
increase of the plasma in volume, he noticed that at the end of five 
days it filled half the frustule, and on the eighth day assumed its cha- 
racteristic form. The Navicul?e then began their curious motions, and 
some days later commenced to multiply by division. Some of the frus- 
tules did not recover, and this he thought was because they had been 
dried too rapidly. 
Searching for Trichina. — M. Tikhomiroff, in making a microscopic 
examination of pork supposed to contain this parasite, digests small 
pieces for half an hour with their weight of chlorate of potash, to 
which he adds four times as much nitric acid. The muscular tissue 
thus treated is agitated with distilled water till the fibrils separate. 
If the trichina is j)resent, a hand lens shows the fibrils with fusiform 
swellings, and the microscope recognizes the creatures.]* 
A Fossil Spider. — ‘ La Nature,’ January 26, 1878, gives a magnified 
drawing of a fossil spider, Attoides eresiformis, discovered by M. Ch. 
Brongniart in the tertiary marls of Aix, in Provence. It is about 
3 • 5 mm. long, and allied to the recent Salticus (Attus) and Eresus. 
The French Academy has awarded 600 francs to M. Bagnis for a 
monograph of Puccinia, and the Commission to which his work was 
referred, observe that authors admit more than 370 species of this 
genus, generally characterized and named according to the plant they 
infest. This implies that one jdant only nourishes one Puccinia, and 
that each Puccinia is only parasitic on a particular plant. M. Bagnis 
* ‘ Der Naturforscher,’ 1, 1878. f ‘ La Nature,’ February 2, 1878. 
