168
N. WALOFF
c. TEE PARASITES OF BROOM MIRIDAE
1. The egg parasitMuch of the data on the egg parasites of the broom Miridae are yet to
be sorted. Dr R. L. Doutt of the Division of Biological Control, University of California, has been good enough to identify for us a number
of mymarids bred from the eggs of Miridae (Richards and Waloff, 1966).
Some of the names are new to the British list and the host records are
probably all new. Eggs of mirids are difficult to keep alive when removed from the host plant and the method which we adopted was to
sleeve 20-25 females of a mirid on a branch of broom for 8-13 days and
remove the sleeve for the rest of the summer. The sleeve was replaced
in the following summer. By this method one cannot be sure of the host
of the parasite, but there is considerable probability. When we dissected twigs for estimations of mirid eggs we encountered a large
number that were parasitised, for instance in 1961-62 83% of Asciodema
eggs were parasitised. In the sleeves, many specimens of the genus
Anagrws were bred, but Dr Doutt is still trying to establish their identity. Among the identified Mymaridae were Anaphes autumnulis Forster
ex sleeve with 0. virescew, Erythmelus goochi Enoch within sleeve with
Ascioderna and Patcasson brachygaster (Debauche) ex sleeve with
0. conwbr.
2. Interactions of the nymphal parasites with their hats
(Ammah-Attoh, 1969; Richards, 1967; Waloff, 1967)
The nymphs of the five species of mirids are parasitised by three
species of euphorine Braconidae of the genus Leiophrm which lay their
eggs mainly in the first two instars of nymphs and emerge as full grown
larvae from the last nymphal insfar which is killed. Varying degrees of
superparasitism were not uncommon, but only one larva completes
development in a host.
Two of the braconids L. heterowrdyli Richards and L. wt?totyli
Richards are new species. Richards (1967) has made a partial revision
of the genus. A small number of these braconids are hyperparasitised
by Mesociaorus sp. (Ichneumonidae). Dr J. F. Perkins kindly examined
some of the adult Mesochorus, but they belong to a group of species
which it is not yet possible to identify. The interactiona between the
hosts and parasites are illustrated in Figs 10 and 12. The emergence of
L. heterocordyli in March or April is perfectly synchronised with that of
its host - Heterocordylus, but in yeam of early spring a few individuals
of Ascioderna and 0. adenmarpi may also be parasitised by this wssp.
Thus the semblance of host specificity is largely determined by the
times of emergence. No other Leiophrm species was bred out of
Heterocordylus nymphs and under experimentdl conditions L. ortkdyli
N. WALOFF
c. TEE PARASITES OF BROOM MIRIDAE
1. The egg parasitMuch of the data on the egg parasites of the broom Miridae are yet to
be sorted. Dr R. L. Doutt of the Division of Biological Control, University of California, has been good enough to identify for us a number
of mymarids bred from the eggs of Miridae (Richards and Waloff, 1966).
Some of the names are new to the British list and the host records are
probably all new. Eggs of mirids are difficult to keep alive when removed from the host plant and the method which we adopted was to
sleeve 20-25 females of a mirid on a branch of broom for 8-13 days and
remove the sleeve for the rest of the summer. The sleeve was replaced
in the following summer. By this method one cannot be sure of the host
of the parasite, but there is considerable probability. When we dissected twigs for estimations of mirid eggs we encountered a large
number that were parasitised, for instance in 1961-62 83% of Asciodema
eggs were parasitised. In the sleeves, many specimens of the genus
Anagrws were bred, but Dr Doutt is still trying to establish their identity. Among the identified Mymaridae were Anaphes autumnulis Forster
ex sleeve with 0. virescew, Erythmelus goochi Enoch within sleeve with
Ascioderna and Patcasson brachygaster (Debauche) ex sleeve with
0. conwbr.
2. Interactions of the nymphal parasites with their hats
(Ammah-Attoh, 1969; Richards, 1967; Waloff, 1967)
The nymphs of the five species of mirids are parasitised by three
species of euphorine Braconidae of the genus Leiophrm which lay their
eggs mainly in the first two instars of nymphs and emerge as full grown
larvae from the last nymphal insfar which is killed. Varying degrees of
superparasitism were not uncommon, but only one larva completes
development in a host.
Two of the braconids L. heterowrdyli Richards and L. wt?totyli
Richards are new species. Richards (1967) has made a partial revision
of the genus. A small number of these braconids are hyperparasitised
by Mesociaorus sp. (Ichneumonidae). Dr J. F. Perkins kindly examined
some of the adult Mesochorus, but they belong to a group of species
which it is not yet possible to identify. The interactiona between the
hosts and parasites are illustrated in Figs 10 and 12. The emergence of
L. heterocordyli in March or April is perfectly synchronised with that of
its host - Heterocordylus, but in yeam of early spring a few individuals
of Ascioderna and 0. adenmarpi may also be parasitised by this wssp.
Thus the semblance of host specificity is largely determined by the
times of emergence. No other Leiophrm species was bred out of
Heterocordylus nymphs and under experimentdl conditions L. ortkdyli