3 i6 ANIMAL DEFENCES 



ringed with black, on the inner surface of the femur of the fore- 

 limb in this species; and that the eye is concealed when the 

 mantis is at rest, because the two limbs are held folded together 

 in front of the body. ' But when danger threatens ', to quote his 

 own words, ' the praying mantis assumes a very peculiar and 

 interesting attitude, which, so far as I know, was first described 

 by Goureau. The long and narrow pro-thorax assumes a ver- 

 tical position, so that the body is supported only by its two 

 pairs of hind-legs. Under these circumstances the insect widely 

 separates the front pair of legs, giving to its long femora a 

 horizontal position, so that the distal ends of them are directed 

 on opposite sides. In this way the eye-spots, which are situated 

 at their bases, stand out conspicuously and are most obvious 

 owing to their colour. The tibiae of the front pair of legs are 

 directed vertically upwards. At the same time the insect lifts 

 up its tegmina [i.e. wing-covers] and unrolls its wings, giving 

 them a horizontal position, and it begins quickly to raise and 

 lower its abdomen, which, rubbing against the posterior edge of 

 the wings at the same time as these continual movements, pro- 

 duces a sound. The mantis can produce the latter artificially 

 by rubbing its wings against some extraneous object." All 

 this is very speculative, but it would appear to be, at any rate, 

 an instance of a spurious warning. 



Mimicking Plant-Bugs. The last case of mimicry among 

 insects to be described here is in some ways the most remark- 

 able of all. An account has elsewhere been given (see p. 208) 

 of the leaf-cutting ants of South America, which cut off and 

 carry home pieces of leaf. W. L. Sclater has pointed out 

 that, associated with these ants, there is a kind of plant-bug 

 which, in colour and shape, actually resembles such an ant, 

 together with the piece of leaf it is carrying (fig. 422). 



MIMICRY AMONG SPIDERS. Spiders often form a favourite 

 diet with insectivorous birds, but it would appear that in various 

 parts of the world some kinds of these creatures obtain a little 

 peace and quietness by pretending to be ants. A very instruc- 

 tive North American species (Synageles picata] of the kind is de- 

 scribed by Peckam. Not only does this form resemble an ant 

 in general form, but also in gait and general behaviour; while its 

 second pair of legs are held up like feelers, the remaining three 

 pairs masquerading as the six legs of an insect. 



