THE ENTOMOLOGIST. IDS 



lays about twenty eggs on each larva that it selects : on their 

 emergence from the egg-shell the young larvae of the ichneu- 

 mon penetrate the skin of the Leucania larva, and appear to 

 feed in company in its interior, coming out only to spin their 

 cocoons after arriving at their full stature : these cocoons 

 are delicately formed of the purest white silk, and the whole 

 twenty, more or less as the case may be, are heaped one 

 upon another, in a most disorderly pile, which has neverthe- 

 less a very pleasing appearance : when the ichneumon is 

 ready to assume the winged state it sheds its skin or pupa- 

 case, and, having pushed this to the bottom of the cocoon 

 by means of its rather powerful legs, it goes to work with 

 its scissor-like mandibles, and, cutting off a cup-shaped 

 segment at the upper end of the cocoon, escapes through the 

 aperture thus made, the little exquisitely white and beauti- 

 fully regular cup remaining suspended among the floss silk in 

 which the cocoons are imbedded : the name of the little 

 ichneumon is Microgaster glomeratus ; it is specifically the 

 same as that so well known for its invaluable mission to 

 check the increase of the large cabbage butterfly (Pieris 

 Brassicae), Those larvas of the Leucania that are so for- 

 tunate as to escape the attention of this parasite, descend to 

 the ground and spin a very loose and shapeless cocoon on 

 the surface of the earth, when in confinement decorating the 

 exterior of the structure with large grains of sand, pellets of 

 frass, or other convenient material it meets with on the floor 

 of the breeding-cage: in this retreat it changes to a smooth 

 brown pupa, of a dull deep red-brown colour, which has a 

 number of abruptly recurved hooks at the anal extremity, 

 two of which, centrally situated, are longer and much larger 

 than the rest ; these are rather more distant at the base than 

 at the extremity, but are nearly parallel, and very near 

 together. Eutomologists who possess my ' Illustrated Na- 

 tural History of British Moths' will find there a very accurate 

 description of the larva, but as that was translated from 

 Boisduval, and not original on my part, I have much 

 pleasure in being able to supply one from nature, having 

 ihe materials both for the description and life-history kindly 

 placed in my hands by Mr. C. J. Watkins, the discoverer of 

 the singular and interesting economy of the species, which 

 he previously published at p. 361 of the third volume of the 



