HOW INSECTS PROTECT THEMSELVES. 
525 
that suddenly extrude yellow or red processes, or which draw themselves 
up and display eye-markings or bands of colour; these are all instances 
of possible efforts at escape by startling or frightening an enemy. They 
are striking to see and, if we could see them in proper proportion might 
be very effective to us ; if a six-foot caterpillar suddenly hissed and two 
six-inch eye-spots glared at me I might be frightened. We cannot 
estimate these things properly because it is not known against what enemy 
they are aimed. It is probable that some are effective, that some were 
once effective or are becoming so and that we misinterpret many. 
The following summary of the more important devices used by 
insects may be of assistance to the student:— 
1. Hard integument. 
2. Hairs and hairiness. 
3. Stinging hairs. 
4. Secretion of distasteful substances. (With warning colouring.) 
5. Use of excrement. 
6. Use of cast skins. 
7. Protective and cryptic colouring form and attitude. Sham¬ 
ming dead. 
8. Batesian mimicry. (Mimicry of a warningly coloured distasteful 
insect.) 
9. Mullerian Mimicry. (Adoption of a general scheme of warning 
colouring by edible as well as inedible insects.) 
10. Misleading and deceptive colouring. 
11. Terrifying devices, sounds, etc. 
12. Resemblance to unpleasant substances. 
In the above pages we have tried to indicate what is known, but we 
have no wish to give the impression that much is known ; every obser¬ 
vation bearing on this subject is worth recording ; every record of one 
insect actually found preying on another is valuable, provided both insects 
are identified at least to genus and if possible to species ; impressions 
gained from general observation are by no means so good as actual 
deductions from a mass of definite facts and it is to be hoped that this 
subject will meet with the attention it deserves in this country. 
We may close this subject by remarking that every student should 
bear it in mind when in the field; the observation of living insects in the 
field is the least prosecuted branch of enquiry and it is well to keep an 
open mind on the subject; an insect mimicking a distasteful insect may 
not now have the same distribution as its model, and this is, of course, a 
source of confusion unless one knows this; there are many other 
misleading factors, but it is a sound practice to look at every insect with 
this problem in view, not straining it, not blinding oneself to facts, 
but honestly endeavouring to penetrate to the truth. 
