Miscellaneous. 151 
The Anguillula then attains its full development, the sexual 
organs, sketched out in the larva, rapidly complete their formation ; 
fecundation takes place ; and from the ova issue the young clayi- 
form larvee, which are speedily set free by the disaggregation of the 
bulb. They creep about in the surrounding soil, that is, if the 
latter is sufficiently damp ; in the contrary case they remain dried 
up and in a state of latent vitality, until the moment when favour- 
able conditions permit them to revert to active life. On arriving in 
the neighbourhood of a normally developed Alliwm they penetrate 
into it, as above stated, and the cycle recommences. 
In this way is explained how the same bulb contains at the same 
time adults, ova, and larvee, and also how the parasite can be trans- 
mitted with the greatest facility from one plant to another, and how 
itis rapidly propagated through a whole plantation. As to the propa- 
gation through the floral organs &c., this is rare, the Anguillula only 
attaining them with difficulty, and this, indeed, precisely on account 
of the initial injuries which it causes in the bulb, and the effect of 
which is to arrest the development of the flowering-stem or to dry 
it up quickly. 
The larvze present a faculty of revivification analogous to that ob- 
served in the larve of the Anguillula of mildewed wheat; but it 
would seem that here this faculty is less powerful. I have, how- 
ever, been able to ascertain it in larve preserved for twenty-six 
months in a dry well-corked bottle; beyond this period I have only 
obtained negative results. The adult Anguillulee, subjected to desic- 
eation, perish quickly, as is also the case when they are exposed to 
a cold of —10° (=14° F.), which has no action on the larve. 
Acidulated water and dilute alcohol instantly kill the adults, while 
the Jarvee retain their vitality in them for some time. 
These facts are obviously comparable to those observed in the case 
of the Anguillula of mildewed wheat, but the onion-parasite con- 
stantly manifests a smaller vital resistance. There is only one 
exception to be made in this particular:—M. Davaine has shown 
that the Anguillula of the mildewed wheat when introduced into 
the digestive canal of fishes, batrachians, and reptiles remains intact, 
whereas if the experiment be repeated with birds or Mammalia the 
worm is soon digested. Now the Anguillula of the onion does not 
undergo any alteration in this same medium, and is to be met with 
again, distinctly characterized, either in the dejections or in the con- 
tents of the intestine, if the animal has been killed shortly after the 
ingestion of portions of the plants containing the worms. One 
might thus be exposed to the error of regarding them as true para- 
sites of the host into which they have been accidentally introduced, 
and in which they cannot acquire any development or undergo any 
encystation, as I have clearly ascertained. 
The agents employed against the Anguillula of mildewed wheat 
may be used against the parasite of the onion ; but the most effica- 
cious process consists in pulling up the diseased plants and burning 
them.—Comptes Rendus, December 24, 1883, p. 1503. 
