THE CYNIPIDH AFFECTING THE OAK. 27 
far as is known the species which produce galls on the 
oak do not take food, nor frequent flowers for nectar ; 
they, however, occasionally imbibe water. Many kinds 
when alarmed fold the wings, tuck their legs and 
antenne close to the body, and remain motionless for 
some time. 
They seldom fly more than a very short distance, 
their distribution being accomplished more frequently 
by the wind than by their own efforts. 
Several observers have recorded the fact that Cynips 
Kollavi is a most lethargic insect. Hundreds of 
imagines may be reared, and only very rarely will one 
be seen on the wing. Nor is this peculiarity confined 
to that species ; it is common to most. 
On one occasion the author opened a gall of 
Dryophanta disticha which contained a mature imago. 
It at once ran about the table, and when a glass was 
placed over it it ran up the side and expanded its 
wings completely, but neither then, nor when the glass 
was reversed, did it attempt to fly. 
Almost all the species cling with remarkable tenacity 
to leaf or twig, or even one’s finger, and it requires a 
sharp and strong puff of wind to dislodge them. 
‘The imagines of most kinds are difficult to rear, 
because it is not easy to maintain the natural con- 
ditions of life. But even when it has been possible to 
accomplish this, success does not often follow. Some 
remain in the larval stage for many months (e.g. 
Andricus glandium, Aphilothrix fecundatriz), and for 
many months more in the pupal condition, and then 
perhaps they will die before the imago ‘stage is 
reached. Doubtless, in their natural surroundings of 
hedges, woods, trees, etc., innumerable multitudes 
never complete their metamorphoses. A few species 
are able to endure great cold. Cameron states that 
Biorhiza aptera appears during frost and snow in 
winter time and deposits ova (loc. cit., vol. iv, p. 3). 
Immediately after leaving the galls the Cynipide 
begin to lay their eggs, and speedily-die. The act of 
