Seats 
ee 
218 DISEASES OF INSECTS. 
nips S.) can escape them, almost every species becoming 
their prey; a circumstance which puzzled not a little 
some of the older naturalists, when they at one time saw 
a fly not remarkable for its colours or brilliancy emerge 
from the curious moss-like Bedeguar of the wild rose, 
and at another were struck by the appearance of one of 
those splendid minims of nature which almost dazzle the 
sight of the beholder?. Immunity, however, from this 
pest seems to have been granted to the gregarious Hy- 
méenoptera; at least none has yet been discovered to at- 
tack the ant, the wasp, the humble-bee, or the hive-bee ; 
in which last, had there been one appropriated to it, it 
could never have escaped the notice of the Reaumurs and 
the Hubers. The solitary bees, however, as we have seen 
aboye®, do. not escape; and Epipone spinipes, a soletary 
wasp which feeds its own young with a number of green 
caterpillars ¢, is itself, when a larva, though concealed in 
a deep burrow, the prey of the grub of an Ichneumon, 
which by means of a long ovipositor introduces its egg 
into its body*. Even these parasites, whose universal of- 
fice it is in their first state to prey upon insects, are them- 
selves subject to the same malady. Ichneumonidan de- 
vourers are kept in check by other Ichneumonidan devour- 
ers. These in some cases are so numerous as to destroy 
the tithe of the kinds they attack*. Thus an ever-watch- 
ful PRovIDENCE prevents these parasites from becoming 
so numerous as to annihilate in any place the species ne- 
cessary for the maintenance of the general economy and 
proportion of animal and vegetable productions. Amongst 
2 Rai. Hist. Ins. 259—, » See above, p. 209; and Voz. I. P. 304, 
© Tid. 346. 4 Reaum. vi. 3038—. 
© Jbid. 11. 454—, 
