260 THE ENTOMOLOGIST. 
species of the genus to be found in Britain, measuring some- 
times as much as 16 mm. across the expanded wings; the 
size, however, varies, specimens often expanding no more than 
12 mm. 
It would seem that the female is much more frequently met 
with than the male; for instance, in February, 1914, L. W. 
Newman sent me twenty-two living specimens which he had 
bred (forced, of course) from larve of various Seside, and all were 
females, and Col. Nurse, who has bred the species commonly, 
has obtained females only. My own experience is that the 
females outnumber the males by ten to one. 
The cocoon is brown, thin, and shining, larger, but not so 
elongate, nor so dark in colour as that of M. thoracicus. It is 
always constructed within the burrow of the host (fig. 8). I have 
specimens bred by Newman from larve of Sesia vespiformis and 
S. culiciformis, taken at Bexley; others bred by Tonge from 
S. culiciformis, July 17th to 24th, 1911; from S. chrysidiformis, 
May 22nd, 1911; and from S. formiciformis, May 11th, 19J2; 
all the hosts taken near Reigate. Harwood has found it 
commonly at Colchester, and Nurse in West Suffolk. I have 
frequently bred it from New Forest larve of S. vespiformis in 
May, and have found the cocoons in burrows of S. tipuliformis 
at Burgess Hill, Sussex, and Sherborne, Dorset. 
M. thoracicus, Nees.—-A well-marked species, easily distin- 
guished by the rufous thorax; always a solitary parasite. In 
the New Forest it appears to be fairly plentiful, and I have 
several times bred it in July and August from larve of Phibalocera 
quercana, also once from larva of Chimabacche fagella, August, 
1913. I have captured it in May. 
Among Fitch’s insects are three males, bred from Phyeis 
betulella by H. Bartlett, June 29th, 1880, and June 80th, 1882; 
also a specimen labelled ‘‘ Darenth Wood.” 
The cocoon is dark brown, narrow, elongate, and constructed 
between the leaves, which are spun together by the host. When 
bred from P. quercana, the cocoon is found under the flat web 
which the larva of the lepidopteron constructs beneath a leaf. 
Marshall states * that Bignell bred it from Noctua triangulum 
and Xylina ornithopus; these seem rather unlikely hosts, and 
it is strange that Bignell makes no mention of them in his South 
Devon list, but merely states that he bred the species from 
‘‘larvee feeding on sallows.” 
This insect is sometimes confused in collections with Huba- 
dizon extensor, L., to which it bears a superficial resemblance. 
M. nitidus (Wesm.).—On May 5th, 1910, I captured a female, 
and on May 15th, 1914, a male which I have no hesitation in 
referring to this species, not before recorded as British. My 
* Trans. Entom. Soc., 1888, p. 196. 
