HYMENOPTERA. 
the tip itself; the instrument being sometimes three times the length of the entire 
body. All the species of the genus are much alike in general appearance, the 
smaller kinds being parasitic on small larvae, and the larger on those of superior 
size. They may be seen flying about in woods in summer, in search of the wood- 
1, Ichneumon pisorius, male, and empty pupa of pine hawk-moth, whence the parasite has emerged; 2, Cryptus 
tarsoleucus, male; 3, Mesostenus gladiator, female ; 4, Ep/hialtes manifestator, male and female, the latter 
laying her eggs. (Nat. size.) 
boring larvae in whose bodies they lay their eggs. With intelligent agility the 
female hurries over the trunk, but by what sense she ultimately detects the 
presence of a larva within, and directs the ovipositor straight down to the spot, it 
is impossible to say; sight can be of 
no assistance, nor, one would judge, 
can touch. Can the antennae be used, 
as the divining rod is supposed to be 
used in the search for water, when 
commonsense methods have failed ? 
Possibly, however, the sense of smell 
assists, and thus the seemingly 
miraculous becomes once more a 
common-place. The females appar¬ 
ently follow the borings of the larvae, 
for it would be next to impossible 
for them to penetrate the hard fibres 
of the timber in which their victims 
burrow. One of the commonest 
members of the family, and one of 
the largest English forms, is Pim'pla instigator, which preys upon many species of 
larvae, especially those so destructive both in gardens and the forests. The perfect 
insect may be seen on tree-trunks, in woods and hedgerows, searching for larvae, 
with its wings raised, ready for instant action. The illustration represents this 
species attacking the larvae of the satin moth. 
Pimpla instigator, female to tlie left, .stinging the larva of the 
satin-moth. To the right is the moth, beneath it the 
pupa, from which emerges the adult, while the male of 
the parasite is seen below. 
