282 
SUMMAIlY OF CURRENT RESEARCHES RELATING TO 
of salivary glands, and the union of their six ductules into a common 
duct which leads into the hypopharynx. This injects the toxin into the 
wound. 
Natural Bepellent Effect of “Warning Colours.”* * * § — Dr. A. Alcock 
describes the behaviour of a very docile young Himalayan bear, which 
showed a marked appetite for grasshoppers. It crunched with every 
sign of relish the common bright-green and dull-brown grasshoppers 
found in Calcutta. On the other hand, it strongly objected to the 
glaring- coloured and evil-smelling Autarches miliaris L., which has 
an abdomen with alternate stripes of black and scarlet, and black fore- 
wings with canary-yellow spots. This insect secretes a most peculiarly 
pungent-smelling frothy fluid ; but after the bear had once smelt it, the 
mere sight of it seemed to be enough for him. Dr. Alcock does not, 
however, say at what distance the bear could smell the grasshopper. So 
far as the observation goes, it seems to him to support the belief £t that 
when an insect has been found by experience to be unpleasant to (taste 
and) smell, it has only to be seen to be avoided ; and that any conspi- 
cuous markings that lead to the immediate recognition of such an insect 
by eyesight and at a distance are likely to be of such benefit to the insect 
as to be acted on by Natural Selection.” 
Ejection of Offensive Liquids by Insects. f — Sig. Y. Izquierdo has 
observed various cases of the defensive ejection of irritant fluids by 
insects. 
Colours of Lepidoptera.J — Mr. A. G. Mayer has made some interest- 
ing investigations on the colours and colour-patterns of moths and 
butterflies. He has analysed the colours in many cases by means both of 
the spectroscope and of Maxwell’s discs, and finds that pure colours are 
very rare, a percentage of black being almost always present. He has 
further studied the development of colour in the wings of Callosamia 
yrometliea and Danais plexijpus Fab., and has confirmed the results of 
previous authors as to the order of development. A series of experiments 
with the wings of butterflies with and without the scales failed to show 
that the latter in any way affect the power of flight, and the author 
therefore concludes that the scales are only of importance in connection 
with colour-production. The second part of the paper contains a detailed 
account of colour-variation in the Heliconidac, the observations, in the 
author’s opinion, all tending to support the theory of mimicry. The 
paper includes a copious bibliography and numerous tables of variation. 
Notes on Termites.§ — Herr K. Czenvinski has found the larvae of 
the “ soldiers” and “nasuti” in a species of Eutermes from Brazil. He 
has also found the frontal gland in imago, nymph, and worker. It is 
multicellular, most complex in the “ nasuti,” and opens at a white spot 
or ££ fontanelle ” where the chitin is very thin. There is a paired and an 
unpaired system of sympathetic nerves, both arising as short strands 
* Journ. Asiatic Soc. Bengal, lxv. (1896) pp. 539-40. 
f Actes Soc. Scient. Chili, 5tli part of vol. v. (1895, published March 1897 !) 
pp. 257-G1 (1 fig.). 
J Bull. Mus. Comp. Zool. Harvard, xxx. (1897) pp. 169-256 (10 pis.). See also 
Proc. Boston Soc. Nat. Hist., xxvii. (1897) pp. 243-330 (10 pis.). 
§ Zool. Anzeig., xx. (1897) pp. 199-202. 
