ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
359 
Compound Nests and Mixed Colonies of Ants.* — Herr E. Wasmann 
— whose studies on ants have been often recorded in this Journal — has 
published a book on the “ Biologie,” i. e. Bionomics, Psychology, and 
History of Ant-societies, discussing especially the compound nests in 
which different species of ants live together more or less habitually, and 
those mixed colonies in which the different species are combined either 
as masters and slaves or as partners. In his fetiological discussion ho 
excludes the possibility of intelligence being a factor in evolving these 
complex states, and regards all the activities as instinctive. 
Ants and Acacias.j - — Prof. C. Keller has demonstrated the myrme- 
cophilous character of Acacia fistula of the Somali lands. This is tho 
first recorded indubitable case of an Old World acacia with symbiotic 
ants. All the trees bear some basally swollen thorns. The swellings 
are white and intact when young, but when older become black and 
exhibit a small circular hole. They contain ants, which Ford in an 
appended note names Crematogaster Chiarinii, C. Buspolii sp. n., and C. 
Acacise sp. n. Observations of a kind now familiar to us show that these 
ants are useful partners of the acacias. Even if ants be absent, as in 
young plants which Schweinfurth reared from seed, the swellings appear, 
“ as if an abnormality had through natural selection in adaptation to 
ants become quite normal,” but the entrance to the hollow swellings 
is made by the ants. This acacia is important as a source of gum, 
which adds an interest to the symbiosis. Moreover, the ants seem 
to have a beetle-partner— Paussus spinicola sp. n. according to Was- 
mann, and the white swellings are mimicked in the cocoons which 
a spider fastens to the branches. Prof. Keller mentions another acacia, 
also from Somali, which possesses swellings in which he found no ants 
but only a small caterpillar. 
Changes of Colour in Schistocerca peregrina.J — M. Kunckel 
d’Herculais finds that this locust undergoes a series of changes in colour ; 
before and after each eedysis the pigment is first rose-coloured. It is 
very interesting to observe that after each moult and metamorphosis 
the excrement of the locust is rose-coloured. The tegumentary deposits 
are colourless when they are not black. The author supposes that tho 
pigment is zooncrythrine or some derived substance. 
Fossil Insects. § — Mr. S. H. Seudder has collected in two handsome 
volumes the numerous memoirs he has from time to time published on 
fossil insects; all Palreozoic Insects had, he says, both pairs of wings 
membranous, but by the middle of the Mesozoic period all existing 
orders of Insects were fully developed in all their essential features. 
S. Arachnida. 
Association of Gamasids with Ants.|| — Mr. A. D. Michael has an 
interesting paper on this subject. He finds that one species of Gamasid 
usually associates with one or two special species of Ants only, or at least 
* Munster i. W., 1801. See Biol. Centralbl., xii. (1892) pp. 123-G. 
t Zool. Anzeig., xv. (1892) pp. 137-43. 
j Comptes Rendus, cxiv. (1892) pp. 240-2. 
§ ‘The Fossil Insects of North America, &o.,’ 2 vols. 4to, New York, 1891, 456 
and 734 pp. See Geol. Mag., ix. (1892) pp. 128-32. 
(1 Proc. Zool. Soc. Loudon, 1891 (1892) pp. 638-53 (2 pis.). 
