(y22"4) 
as a result of our study of these activities is that their com- 
plexity and perfection have been greatly over-estimated. We 
have found them in all stages of development and are con- 
vinced that they have passed through many degrees, from the 
simple to the complex, by the action of natural selection. 
Indeed, we find in them beautiful examples of the survival of 
the fittest.” * 
As long ago as 1889 the present writer had argued that the 
Lamarckian interpretation of the instincts of Ammophila or 
Sphex introduced the same difficulty as that alluded to in the 
discussion of the cocoon-making instinct. It implied a gift of 
prophecy, a knowledge of what would happen to offspring after 
the burrow had been sealed and left to its fate. 
Another powerful argument is derived from the comparison 
between the instincts which are performed but once and those 
which are performed many times in a single life. Various 
elaborate performances are undertaken but once in an insect’s 
* See the review of Dr. and Mrs. Peckham’s work in ‘ Nature,” vol. 
lix, 1898, pp. 465-468. , 
+ The argument was used in the ‘‘ Discussion on Acquired Characters ” 
in Section D of the British Association at Newcastle, Friday, September 
13, 1889. See Report, p. 620, where, however, only the title of the paper 
is printed. The following sentences are quoted from the abstract in 
‘** Nature,” vol. xl, 1889, p. 610 :— 
‘‘ With regard to instinct, Dr. Romanes had suggested a difficulty— 
that was, the instinct of certain wasps to sting and paralyze the nerve 
centres of their prey. But it must be remembered that the benefits 
arising from this instinct were felt not by the wasps themselves, but 
by their progeny.” 
In ‘Proc. Boston Soc. Nat. Hist.,” vol. xxvi, 1894, p. 392, the argu- 
ment is stated in greater detail as follows :— 
“The wasp-like insect has no opportunity of learning by experience 
because it can never know whether the larva stored up is a failure or a 
success. Ifthe larva had not been stung, or, accepting the received accounts, 
had been stung in the wrong place, it would struggle and perhaps kill the 
young grub ; or dying of starvation it might dry up and be useless as food. 
But the Hymenopteron never goes back to inquire. It makes all the 
difference to the young grubs whether the food provided for them is in an 
appropriate condition or not, but it makes no difference whatever to the 
parent insect. The latter seals up the chamber in which its eggs have 
been laid and never opens it again ; it has no chance of noting the failure 
or the success of the food it has provided. It is clearly a case like that of 
the cocoon, which cannot be explained on the Lamarckian theory and 
must be explained on the Darwinian. And this latter interpretation is 
easy ; those insects which possessed the nervous mechanism impelling 
them to provide food in an appropriate condition gave to their offspring 
the opportunity of surviving and inheriting the same instinct; while 
others, impelled to perform less efficient actions, were thereby cut off from 
any representation in the next generation.” The passage has been slightly 
modified. 
