250 SENSES OF INSECTS. 
cated to its sensory. A similar disproportion is observ- 
able between the antennae and ovipositor of Pimpla 
Manijestator, before signalized a . Bees, when collecting 
honey and pollen, first insert the organs in question into 
the flowers which they visit ; but, as I have more than 
once observed, they merely insert the tip of them. If 
anthers are bursting, or the nectar is exuding, these 
processes probably are attended by a slight noise, or 
motion of the air within the blossom, which, as in the 
last case, affects, without immediate contact, the ex- 
ploring organs. 
If the structure of antennae be taken into consideration, 
it will furnish us with additional reasons in favour of the 
above hypothesis, with regard to their primary function. 
We shall find that these organs, in most of those insects 
which take their food by suction, are usually less gifted 
with powers of motion, than they are in the mandibulate 
tribes ; so that in the majority of the Homopterous He- 
miptera and Diptera, as is generally acknowledged, they 
cannot be used for touch. Under this view, they may 
be divided into active antennae and passive antennae : of 
the former, the most active and versatile are those of the 
Hymenoptera. By means of them, as was before ob- 
served b , their gregarious tribes hold converse, and make 
inquiry — frequently without contact — in the pursuit and 
discharge, if I may so speak, of the various duties de- 
volved upon them by Providence. Amongst active 
antennae, some are much more complex in their struc- 
ture than others — a circumstance which is often charac- 
1 See above, p. 218. b Vol. II. p. 64, 198—. 
