208 
PARASITES OF GIPSY, AND BROWN-TAIL MOTHS. 
Occasionally, however, a few secondary parasites have been reared 
from puparia from abroad either because these puparia were col- 
lected in part in the open or because the parasites were of species 
which attacked the primary parasite during the life of the primary 
host. The number of secondary parasites having such habit is 
apparently very limited, and it has been definitely proved of but two 
genera, namely, Perilampus among the chalcidids and Mesochorus 
among the ichneumonids. The latter has never been reared as a 
parasite of any tachinid. 
Because of the rather extraordinary precautions which were taken 
to avoid introducing into America the secondary, together with the 
primary, parasites of the gipsy moth and the brown-tail moth, the 
whole question of secondary parasitism is worthy of considerable 
attention in anything which purports to be a history, however 
abbreviated, of the operations conducted at the parasite laboratory. 
In the case of those attacking the tachinids it is better that they be 
briefly considered en masse, since there are very few among them 
with host relations restricted other than physically. 
Perilampus cuprinus Forst. 
Actually, only a very little is known of this species from first-hand 
investigations further than that it is occasionally reared from puparia 
of any species of tachinid parasitic upon the browmtail moth or gipsy 
moth in Europe, and under circumstamces which strongly indicate 
a habit of making its attack before the death of the primary host. 
At the same time it is felt that much is known of the probable habits 
of this species through analogy as the results of Mr. Smith's studies 
of the early history of the allied American species, Perilamjms 
hyalinus Say, which attacks the parasites, both hymenopterous and 
dipterous, of the fall webworm. Presumably, like the American 
species, its minute first-stage larva, or ^planidium," gains access to 
the host in some maimer not quite clear, and after wandering about 
in its body for a time enters the bodies of such parasites as it chances 
to encounter. 
That a secondary parasite having such habits might be expected 
to be peculiarly a parasite of the parasites of one particular host 
rather than of the same or similar parasites of another host, coupled 
with the fact that extraordinary precautions were obviously necessary 
to provide against its accidental importation, made Perilampus 
cuprinus appear peculiarly abhorrent, and for a time following the 
discovery of the early habits of P. liyalinus precautions against (he 
importation of its congener were redoubled. In the course of time it 
was determined that it was never present in sufficient abundance 
to make it at all probable that it was a parasite of the gipsy moth or 
the brown-tail moth parasites to anything like the extent to which 
