448 
DISCURSIVE NOTES ON THE 
It may be argued that such differences in expertness them- 
selves imply the presumption of intelligence, which might 
be expected to vary in different animals. 
More especially in the case of the last observation, when 
the Sphegid found her way back in such a direct manner, does 
it seem justifiable to call in the use of memory. Now memory 
implies intelligence. But we are begging the whole question 
here ; for there is no word, in the operations of instinct, to 
compare with memory, which is only for intelligence. ‘ In- 
stinctive memory ’ would be an absurd phrase ; yet we have 
no word in English for what it implies— namely , a process of 
instinct comparable to the process of intelligence called 
memory. 
The Eossors are of interest in so many ways that, in a 
discursive paper such as this, one is hard put to it to keep 
within even broad limits. Eor instance, there is their relation- 
ship to man and his environment — i.e. their bionomics in con- 
nection with man. In the case of the Bembecidce, their direct 
relation to the health of man and his domestic animals is 
obvious, for they prey almost exclusively 1 upon two-winged 
flies, and more particularly upon the blood-suckers which 
transmit diseases. That they prey upon Tabanidce has long 
been known ; that they also prey upon Glossina, the Tsetse 
flies, has only been made known in recent years, owing to the 
increased attention paid to these very important flies. 
Consider the Sphegidce, some of which, for each larva, store 
up a number of small caterpillars ; so that during the working 
life a single mother might destroy several dozen harmful 
caterpillars. Many Sphegids store up such destructive insects 
as crickets, grasshoppers, cockroaches, &c. It must be re- 
membered that each Eossor has a certain type of prey — often 
a certain species only — on which the young are fed, and this 
is sought out from its most secret hiding-places. 
On the other hand, certain Sphegids, and all Pompilids — 
so far as I have seen — prey upon spiders, in which case their 
activities by destroying useful creatures are positively against 
man’s interests. Then there is the more complicated point 
1 I have recently seen one pounce upon and carry off a Hesperid or ‘ skipper * 
butterfly, drinking at the edge of a puddle. 
