492 NATURAL HISTORY. 3 
wimble itfelf, of an admirable ftructure, confifts ef | 
three pieces: Iwo collateral onés, hollowed out into "y 
a gutter, ferve asa fheath; and ‘contain a compact, © 
folid and dentated ftem ; along which runs a groove, 7 
that conveys the egg from the animal, which fupports 
the wimble with its hinder legs, left it fhould break ; © 
aud, by a variety of movements, which it dexteroufly 
performs, it bores through the building, and depofits © 
one or more eggs, according to the fize of the ichnen- © 
mon, though the largeft drop but one ortwo. Some ~ 
agglutinate their eggs upon caterpillars eggs, though © 
very hard, and depofit their ownin the infide: When 
the Jarva is. hatched, its head.is fo fituated that it 
pierces the caterpillar, and penetrates te its very en- 
trails: Thefe larve pump out the nutritious juices of 
the caterpillar, without attacking the vitals of the 
creature ; which appears healthy, and even fometimes | 
transtorms itfelf to a chryfalis. itis not uncommon | 
to fee caterpillars fixed upon trees, as if they were 
iitting upon thole their eggs; and it is afterwards dif- 
covered that the larve, which were within their bod- © 
ies, have {pun their threads, with which, as with | 
cords, the caterpillars are fattened down, and fo per- 
ifh iniferably. 2 . 
The ichneumons yérformed fpecial fervice in the 
years 1731 and 19732, by -multiplving in the fame pro- 
portion as did the caterpillars : Their larve deftroyed 
more of thei than could be effected by. human induf- 
try. Thofe larva, when on the point of turning into 
chryfatids, fpin a filky cod. Nothing is more fur-— 
prifing and fingular, than to fee thofe cods leap, when 
placed on the table, or hand. Plant lice, the larvez 
of the curculiones, fpider’s eggs, are allo fometimes 
the cradle of the ichneuimon fly. Carcafes of plant 
lice, void of motion, are often found on rofe tree 
leaves. Chey are the habitation of a {mall larva ; 
which, after having eaten up. the entrails, deftroys 
the fprings and inward economy of the plant houte, 
performs its metamorphofis under fhelter of the pelli- 
cule which enfolded it, contrives itfelfa fmall circu- 
lar outlet, and fallies forth into the open air. oo 
There are ichneumons in the woods, which dare 
attack fpiders, run them through with their Ming, 






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