242 THE entomologist's kecord. 



almost completely receives the tibia and tarsus, and thus their bright 

 decorative colours can be concealed from the eyes of their enemies. 

 In addition to this, even though the tibife of these insects are thin, in 

 some of them, for further protection, the bright colours are disposed 

 only along the inner surface ; thus, for instance, in Ac rid i inn aciji/jitium, 

 only the inner surface of the tibia is lilac-coloured while the outer is 

 of the same grey tint as the rest of its body. In species of Kretnuhia 

 we likewise notice that only the inner surface of the tibia is red or 

 violet, but here, adaptation goes even further and is enhanced in that 

 only the inner row of tibial spines is brightly coloured, while the 

 outer one, as well as the joints of the tarsus, is entirely devoid of 

 bright hues. Thus we see that, in the locust family of Orthoptera, 

 nature gave preference to the long hind-legs for the development of 

 brilliant hues and that even there she arrayed them with great pre- 

 caution. 



But even in this family of Orthoptera species are met with whose 

 bodies are coloured so gaily that a priori, without preliminary experi- 

 mentation, one can conclude that these insects are not fit as food for 

 insectivorous animals.'' It is self-evident that insects thus protected, 

 i.e., by unpleasant taste and perhaps poisonous properties, wnll not 

 answer to those general conditions of the distribution of bright colours 

 spoken of above. As an illustration I will take a South American 

 representative of the family, Acridiidae, described under the name of 

 Acridimii tarsatinii. This insect is so brightly coloured that it more 

 resembles a gaudily coloured toy than a living being. Its entire body 

 is bright green, but the upper part of the head is orange-red. The 

 femora and tibi* of the first two pairs of legs are tinged with red, 

 yellow and black, and all the tarsi are red and black. The hind 

 femora are yellow on the outside having a black spot and ring near 

 the top. The hind tibias are red at the base, then follows a black 

 ring, then abroad yellow one, and at the ends are black again. Hence 

 we see that, in this Orthopteron that does not need any protective 

 colouring, all the bright colours are not hidden as in most of those 

 considered above, but, on the contrary, are conspicuously displayed. 

 Those parts of the body that, in other Orthoptera, bear the bright 

 colours, are either coloured equally bright with the other more exposed 

 parts, or even more modest, as, for example, the lower and inner sur- 

 faces of the posterior femora in Acridiinn tarsatiim. But, beside that, we 

 find here a still more important and interesting phenomenon ; the 

 hind tibife adorned with their bright hues present no danger to the 

 unsavoury insect, so that there is no necessity whatever for concealing 

 these bright colours in the groove of the inner surface of the femur. 

 In connection with this we also find a somewhat different structure of 

 the femur in A. tarsatinn. Its hind femora are comparatively much 

 thinner than in other Acridiidae with a protective body coloration, and 

 the groovelet on the inner surface is, comparatively, very little 

 developed. And thus we come to the conclusion that the bright 



* Similar facts are known also in other cases of insects belonging to the order 

 Orthoptera. Thus, Horn observed that birds and lizards always turned away 

 from one brightly-coloured Indian species when it was offered to them (Froc. Ent. 

 Soc. London, 1.SG9, p. xi). Upon piercing the thorax of several Orthoptera, a 

 strong odour is perceived, which is given off by the liquid issuing from the pierced 

 place (Serville, Hist. Nat. des Orthopt., p. 219). 



