F. M. CAMPBELL-ON" INSTINCT. 
127 
to their frequent destruction and consequent renewal as to the 
necessities of the situation. A species such as the garden-spider 
(Epeira diadema, Blackw.), which is continually making webs, offers 
greater opportunity for the development of dexterity in construction 
than one like the house-spider (Tegenaria Guyonii, Guer.), whose 
snare is uninjured by the prey, and lasts for months if undisturbed. 
The condition of its web is indeed so unimportant that the spider 
will take possession of a dirty abandoned tenement of another of 
the same species as readily as a whelk will an empty shell. 
Instincts of Neuter Insects. 
It must be admitted that the development of habits and structure 
of neuter insects, such as seen amongst ants and bees, cannot be 
traced in the present state of our knowledge. The most that can 
be done is to show that there is no anomaly. If we take, for an 
instance, the neuter-bee, we find a cell-maker and a pollen- and 
honey-collector with its second* and third pair of legs specially 
adapted for the purpose. The drone and the queen—its parents— 
have neither the structure nor the habits, and it would therefore 
appear as if selection could not have acted through them. I have 
noticed, however, that there is a variation in the tibia and first 
tarsal joint of the third pair of legs amongst queens and drones, 
and these are the parts specially adapted in neuters for the collection 
and conveyance of pollen. The variation consists more especially 
in the convexity of the tibial joint, and the dimensions of its two 
extremities, quite independent of the size of the queen. The origin 
of secondary sexual characters may be due to physiological corre¬ 
lations, and, if this be so, there is no reason why there should 
not be secondary neuter characters. These may have been developed 
into their present form by natural selection. The larvae certainly 
receive less food than the perfect insects. Darwin’s hypothetical 
explanation of the specialised instincts and structures of neuters is, 
that “ selection may be applied to the family as to the individual,” 
illustrating the idea as follows :—“ Such faith may be placed in 
the power of selection that a breed of cattle always yielding oxen 
with extraordinarily long horns could, it is probable, be formed by 
carefully watching which individual bulls and cows, when matched, 
produced oxen with the longest horns, and yet no one ox would 
have propagated its kind.”f The difficulty to many in accepting 
the above suggestion as applicable, is the degree of specialised habits 
for which it is supposed to account in the neuter insect, but the 
degree is a secondary matter, explained by the operation of natural 
selection, when once we can reconcile structure and a corresponding 
habit appearing persistently in certain offspring, and which are not 
to be found in the parents. If this difficulty be surmounted, the 
rest is clear, for the queens of the hives in which the workers are 
best adapted lor the collection of honey and pollen, leave a greater 
progeny both of drones and queens than are bred in hives with 
* I refer to the spur on the tibia. 
f ‘ Origin of Species,’ 6th ed., p. 230. 
VOL. III.-PART III. 
