The true mushroom itself is to a great extent a dung-borne species, therefore mushroom-beds are always liable to an invasion from other dung-borne forms. The spores of all fungi are constantly floating about in the air, and when the spores of dung-infesting species alight on a mushroom-bed they find a nidus already prepared that exactly suits them; and if the spawn of the new-comer becomes more profuse than that of the mushroom the stranger takes up his position at the expense of the mushroom.
A species of Acarus is recorded as infesting a store of powdered strychnine and feeding on that drug, so poisonous to larger organisms. Reference to literature (40).
The louse of monkeys is now generally considered as forming a separate genus (Pedicinus), but the greater part of those infesting domestic and wild quadrupeds are mostly grouped in the large genus Haematopinus, and very rarely is the same species found on different kinds of animals.
Root-infesting forms, Root-infesting forms, znd generation, 2 Winged forms, 1 Root-infesting forms, 3 rd generation, Wingless female.
Meanwhile French corsairs from St Malo and Dieppe had been active in infesting the West Indies and the trade route followed by the Spanish convoys.
In one case described by Kuckuck the chromaphores of the infesting algae are absent, a circumstance which points to a complete parasitism.
The common small white butterfly of Europe (Pontia or Pieris rapae) is now established in North America; and the march of the jigger, or foot-infesting flea (Sarcopsylla penetrans) of tropical America, across Africa, has taken place in quite recent years.