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 larvae of various Sesidae, 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 larvse of Sesia vespifurmis and 

 S. culiciformis, taken at Bexley ; others bred by Tonge from 

 S. culiciformis, July 17th to 24th, 1911 ; from S. chrt/sicliformis, 

 May 22nd, 1911 ; and from >S'. formiciformis, May lltb, 1932 ; 

 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 larvae of S. vespiformis in 

 May, and have found the cocoons in burrows of S. tipidiformis 

 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 larvae of Phihalocera 

 quercana, also once from larva of Chimahacche fagclla, August, 

 1913. I have captured it in May. 



Among Fitch's insects are three males, bred from Phyeis 

 hetulella by H. Bartlett, June 29th, 1880, and June 30th, 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 

 " larvae feeding on sallows." 



This insect is sometimes confused in collections with Euba- 

 clizon extensor, L., to which it bears a superficial resemblance. 



M. nitidus (Wesm.). — On May 5th, 1910, 1 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. 



