290 BRITISH [CHNEUMONS. [ Polyblastus 

Curtis (B.E. 399) has made some remarks.” “All the females I have 
seen have had these nits attached to them; each appears to me to be an 
animal contained in a bladder which has a peduncle at the lower end, by 
which it is attached to the base of the oviduct; they are there nourished, 
but whether the animal ever leaves the sac I am not able to determine: 
I think it probable since I found that the bladders attached to the upper 
side of the abdomen of the female Dy/icus marginalis contained an 
Fiydrachna,” which is not an analogous case for, whatever their economy, 
the present are certainly the offspring of their host. Westwood also is at 
fault when he proceeds, “It is evident that the insect, probably in the 
agony of death ” (as first suggested by Gravenhorst), “had extruded its 
already developed and impregnated eggs, without being able to place 
them in their true locality, whence they remained attached to the 
abdomen of the parent,” but the evidence goes to prove that these cor- 
puscules are always larvae, with the assumption that the eggs are gestated 
within the female abdomen, like so many of the Diptera. Dr. Hartig 
also published a Memoir upon the pedunculated eggs of various 
Ichneumonidae (Wiegm. Arch. iii, tab. 4) exhibiting the abdomen of his 
undescribed Polyblas/us cancer, bearing a very great number of eggs 
attached to its extremity beneath, and P. caudazus in the act of depositing 
a pedunculated egg. But scant attention appears to have been since paid 
the subject, which is biologically most fascinating. Little doubt can re- 
main that the extrusion of the eggs or larvae is perfectly normal, for the 
great majority of the females captured bear such clusters which Fons- 
colombe, even in 1849, considered to be true eggs; and the subject is 
referred to, though no species are mentioned, by Rev. J. G. Wood in 
Insects at Home, p. 322. Quite possibly, in order to avoid individual 
death through the superabundance of their hosts’ vitality, whole broods of 
these parasites are deposited at once upon the Tenthredinid host larva, 
and are, as Curtis occultly pronounces, nourished by the female until they 
arrive at a sufficiently vigorous condition to render them immune from 
such a contingency; but I fail to find any reference to this effect yet pub- 
lished. 
Table of Species. 
(2). 1. Antennae white-banded; legs short 
andsstout |. B. S: .. I. ANNULICORNIS, G27. 
(1). 2. Antennae not white-banded; legs 
usually subelongate. 
(34). 3. Scutellum not pyramidal, at most 
simply convex. 
(5). 4. Apical hind tarsal joint thrice longer 
than penultimate .. aa .. 2. PARVULUS, Grav. 
(4). 5. Apical hind tarsal joint hardly 
double penultimate. 
(23). 6. Centre of abdomen mainly red, or 
hind tarsi white-banded. 
(8). 7. Scutellum and mesonotal  vittae 
bright flavous 4 sf se 
(7). 8. Scutellum and mesonotum immacu- 
late black. 
(20). g. Areolet entire or subentire. 
(11). 10. Hind legs entirely black ; abdomen 
obscurely red fr ni af 
3. BRIDGMANI, Par. 
4. UNICINCTUS, Bridg. 
