41 8 THE NATURAL HISTORY 



proved, however, to be myriads of tiny larvae, averaging 

 perhaps half-an-inch in length each, slender, somewhat 

 tapering at both ends, and of a green colour when 

 full fed. They were exceedingly active, and on the 

 slightest touch would wriggle themselves off from the 

 leaf on which they were feeding, let themselves down 

 by a silken thread, and remain suspended till the cause 

 of alarm had subsided, when they would regain their 

 former position. So incredible were their numbers, 

 that on a single plant of moderate size and taken at 

 random, I counted upwards of two hundred and forty ! 

 and before the end of the first week in August, 

 every leaf, for the space of more than an acre, was 

 completely reduced to a parched-up skeleton : not a 

 turnip escaped them, and by the middle of the month 

 you might have looked in vain for the smallest vestige 

 of a green leaf on the field of their depredations ; and 

 to this day (Oct. 29th, 1837) it is as bare as if nothing 

 had been sown there. Similar patches from a like 

 cause may be seen in two or three other fields in this 

 neighbourhood, where a most excellent crop is yielded 

 in every other part. On the 9th they began spinning 

 their cocoons, which are of the most beautiful net-like 

 texture, some on the dried fibres of the turnip leaves 

 and others upon the ground. The perfect insects 

 emerged about the 2Oth; but out of seventeen 

 cocoons five moths only were hatched, while the 

 remaining twelve produced the accompanying para- 

 site."* The destructive powers of this moth will 

 perhaps be fully appreciated, if we add that it does 

 not exceed two lines and a half in length ! 



The last three species of this group differ from all 

 our other moths, in the fact that their wings are so 

 deeply divided between the nervures, that they present 

 the appearance of several separate feathers or fringed 

 rays standing out laterally on each side the body. 

 They are known to entomologists as Plume Moths, 

 This was Campoplex panisciis, an Ichneumon. 



