imc) = = NATORE 
THURSDAY, FEBRUARY 12, 1914. 
- A GERMAN’ INTRODUCTION TO THE 
STUDY OF MIMICRY. 
Mimikry und Verwandte Erscheinungen. By Dr. 
. Arnold Jacobi. Pp. ix+216. (Braunschweig : 
F. Vieweg und Sohn, 1913.) Price 8 marks. 
HE scope of the work before us is sufficiently 
indicated by a list of its main sections. A 
brief general introduction is succeeded by a division 
of the subject under nine heads :—(i.) Protective 
Colouring; (ii.) Protective Resemblance; (iii-) 
Warning Colours; (iv.) Mimicry or Protective 
Imitation; (v.) The Imitation of Aculeate Hymen- 
optera, or “Sphecoidie’”’; (vi.) The Imitation of 
Ants, or “Myrmecoidie” ; (vii.) The Imitation of 
Beetles; (viii.) Mimicry in Lepidoptera; (ix.) The 
General Characteristics of Mimetic Lepidoptera. 
Some of the principal memoirs in the literature of 
the subject are named in a short list at the end 
of the volume, but anything like a complete treat- 
ment is manifestly impossible in a work of this 
size. 
Protective colouring (Schutzfarbung) and pro- 
tective resemblance (Schiitzende Aehnlichkeit) are 
the terms employed by the author for the two 
kinds of cryptic colouring which have been called 
general and special protective resemblance. In 
the first the animal seems to melt into its sur- 
roundingss; in the second it resembles some actual 
object. No mention is made of Thayer’s interest- 
ing combination of the two principles in animals 
with a general obliterative colouring upon which 
are represented the details of the normal environ- 
ment. Nor is there any reference to the same 
naturalist’s brilliant interpretation of the white 
under-sides of animals. roe -- 
The criticism, urged on p. 8, that we do not 
know whether the cryptic appearance is truly 
advantageous and really exists for the eye of the 
insect-eater can only be fully met by increased 
knowledge. In- the meantime it is obvious that 
certain birds do hunt for their prey. over tree- 
trunks that are not swept bare, even after many 
months of intermittent searching, but still harbour 
sufficient pupe to keep up the average num- 
bers of the species. We know too that birds 
will assemble in order to feed, when insects 
which must ordinarily be searched for are 
driven out by a grass fire or by “Driver” ants 
on the raid. And no one who has watched the 
pursuit of a cryptically coloured moth by birds in 
the immediate neighbourhood can doubt that it 
would have been attacked when at rest if only 
it had been seen. frepign” 
NO. 2311, VOL. 92] 
me 653 
The resemblan acide to thoriisj 
bark, &c., is dismissed by the author (p. 15) as 
examples of ‘““Museum Mimicry,” for the very 
inadequate reason that these Homoptera are 
“mighty jumpers,” and when disturbed “ disappear 
after the manner of the flea.” Well-concealed 
species are generally swift in their movements 
when they are disturbed. Furthermore, W. A. 
Lamborn has shown that the dark, bark-like 
West African Membracids are ant-attended when 
found on green stems. Companies of individuals 
are always found on old bark, as are females 
engaged in egg-laying—a very prolonged opera- 
tion, lasting from thirty-six to forty-eight hours, 
during which the insect clings tenaciously to the 
ege-mass and is with difficulty disturbed (Trans. 
Ent. Soc., 1913, pp. 494-7). The author admits 
the wonderfully ant-like appearance of some 
tropical American Membracids, but rejects an 
interpretation based on the theory of mimicry 
because ants run and Membracids jump. The 
idea of a second line of defence does not seem 
to have occurred to him; and yet in nearly all the 
examples he accepts there is a second line, de- 
pending on powers of flight very different from 
those of the model. 
The author has evidently taken considerable 
pains in studying the work that has been done in 
this country and expresses regret that his com- 
patriots have not taken a larger share in it. There 
is, however, one subject which has escaped him, 
viz., the power of individual adjustment to the 
; colours of the environment as exhibited by insects. 
On this power he can find nothing in English 
except ‘“‘a meagre experiment . . . on butterfly 
pupe ”! (p. 25). The present writer is, moreover, 
bound to disclaim the honour of having influenced 
some of the names that are here set down—for 
example, the late Thomas Belt, whom he never 
had the pleasure of seeing, but to whom, for the 
‘Naturalist in Nicaragua,” he owes a deep debt 
of gratitude. Although the author writes with 
generous appreciation of British work, and 
appears to agree with its general tendency, he 
differs strongly from many conclusions on special 
points, and offers criticisms which it will be a 
pleasure to attempt to meet on some future occa- 
sion. 
It is satisfactory to find the recognition, on 
p- 35, of a fact often forgotten—“ that even the 
protective adaptation which is apparently the most 
perfect does not give security against detection— 
that creatures thus equipped have their special 
foes which can find them out, at least when driven 
by hunger.” Similarly the polymorphism of the 
| leaf-butterflies, Kallima, &c.—a stumbling-block to 
BB: 
