Proceedings of the South African Philosophical Society. Xxxix 
way they do. In South Africa several of them, belonging to the 
genus Julodis, have on the upper and under sides a mass of yellow 
or reddish tufts, giving them a most peculiar appearance, and remind- 
ing one at once of the yellow clusters of the ‘‘ Doornbosch ”’ (Acacia 
horrida), If the resemblance of these insects (the congeners of which 
elsewhere have bands and not tufts) to the yellow clusters of the 
acacia flowers was adduced as a proof of an assimilation to the sur- 
roundings, this would be but partially true, because only two species 
are found on the acacia in bloom. Others, as often as not, are found 
on graminaceous plants, or on bushes not always in flower at the 
time of their appearance, which lasts at most one month. The time 
of their appearance in Namaqualand, and in the south-west of the 
Cape Colony, where the species are most numerous, does not coincide 
with the flowering of the acacia. It is, however, quite possible that, 
at some remoter period, acacias were more numerous, and that the 
insect has adapted itself to other conditions of life, retaining still his 
acquired characters. 
Il.—Display of brilliant colowrs. 
(a) Indicating that the species is unpalatable. 
I have dealt so far only with colouration, which, combined with 
other modifications, is useful for aggressive resemblance in the case 
-of carnivorous insects, or for protective purposes in the case of non- 
carnivorous insects. But there is another kind of protective colouring 
ditfermg from the two mentioned, inasmuch as it consists in the dis- 
play of bright colours to show the enemy that the bearers of the 
same are unpalatable. These colours are only displayed by non- 
carnivorous insects, and warn insectivorous animals that the individual 
is to be avoided. 
In the examples found in South Africa, such warning colours occur 
in species which have a special gait, or a comparatively slow, lazy 
mode of flight, possibly acquired through the consciousness of the 
efficacy of the colours. 
It is in the Orders OrTHOPTERA, HEMIPTERA, and LEPIDOPTERA 
that the most striking instances of this kind of protection are found. 
In the OrtTHoPTERA, the huge species of Phymateus (P. verrucosus, 
leprosus, morbillosus) with red or green thorax, blue and green upper 
wings, and roseate or purple under wings are conspicuous enough 
objects in the landscape. Ochrophlebia carinata, ligneola, &e., never 
lose the chance of taking a short flight to show their purple or 
magenta under wings. The same portion of Zonocerus elegans 1s 
e 
