CONTRIBUTIONS TO OUR KNOWLEDGE OF BRITISH BRACONIDA. 253 
pennaria, July 10th, 1910; Gonodontis bidentata, October 19th, 
1913; Metrocampa margaritaria, March 31st, 1915 (in this case 
the parasite larve left their host on October 14th, 1914, so that 
it would seem that the winter is passed in the larval state within 
the cocoon, although I have also bred the insect in November 
from larve of M. margaritaria) ; commonly from larve of Pecilo- 
campa popult in early June (quite 50 per cent. of the full-grown 
larvee of P. populi obtained by beating in the New Forest usually 
produce this parasite); very commonly from full-fed larve of 
Diloba ceruleocephala; Miselia oxyacanthe, Jane 5th, 1911; 
Asteroscopus sphinx, June 8th, 1911; and Catocala promissa. 
May 25th, 1912. 
The broods usually consist of from eleven to sixteen 
individuals, though I have obtained as few as three from 
M. margaritaria. 
Difficilis, Nees.* 
Nees von Essenbeck himself. considered his difficilis to be a 
synonym of caié, Bouché,} and it is difficult to understand why 
Reinhard should have disagreed with this. At any rate, the 
insect with which we are now dealing, i.e. that redescribed by 
Reinhard { as difjicilis, Nees, is certainly very distinct from cata. 
Differs from insidens in having hyaline wings and a much 
shorter second abdominal segment. 
This is the parasite of Bombyx rubi, many of the half-grown 
larve of the host falling victims in August, while often two-thirds 
of the full-grown caterpillars succumb in October. The parasites 
of the later generation pass the winter as larve within their 
cocoons, the imagines emerging in April. That there is at least 
one generation in the year which cannot prey on b. rubi is certain, 
and I would suggest B. quercus or B. trifolii as likely hosts. 
The cocoons are flesh-coloured and not attached to the host 
as in insidens, though they may occasionally be seen entangled 
among the long hairs of the caterpillar. Marshail gives a very 
long list of other hosts for this species, partly copied from con- 
tiriental authors and partly recorded from Bignell’s collection, 
and tells us that the cocoons are often buff-coloured or yellow. 
Although I have obtained such cocoons from some of the hosts 
mentioned by Marshall, I cannot think that the makers belong 
to this species. If not an undescribed species, which I think 
probable, they are, I believe, more likely to be pale examples of 
insidens. Probably a study of the male genitalia would settle 
this point. Bignell, writing after Marshall had published the 
lists of hosts in ‘Trans. Entom. Soce.,’ gives only b. rubi as the 
host.§ 
* *Mon.,’ i, 182. 
+ ‘Mon.,’ ii, 402. 
{ ‘Berl. ent. Zeit.,’ 1881, p. 35. 
§ ‘Trans. Dev. Ass.,’ xxxill, p. 657. 
