788 
ANNUAL REPORT OF NEW TORE 
TOBACCO-WORM. KILLED IT INTERNAL PARASITES* THEIR HABITS. 
to the body and reach two-thirds of its length, and interposed between 
them at their ends is a single pair of the leg-sheaths, which exactly equal 
them in length. Along their lower edges are the antennse-sheaths, regu¬ 
larly marked with transverse impressed lines and tapering to a very acute 
point on each side of the end of the tongue-case. The rings of the body 
are closely and confluently punctured on their anterior sides and show 
numerous transverse irregular scratches and fine wrinkles towards their 
posterior edges. The breathing pores form a row of oval impressions 
along each side, each having two acutely elevated lines and between them 
a narrow elliptic cleft. On the back at the base of the abdomen is a 
smooth black transverse ridge interrupted in its middle. The three short 
rings at the hind end are rapidly narrowed, forming a conical point having 
at its tip two small thorn-like points, one larger than the other. 
We come in the next place to consider the natural enemies and destroy¬ 
ers which restrain this insect from becoming excessively multiplied and 
numerous. Large and vigorous as this tobacco worm is, enveloped in such 
a tough, leathery skin, and jerking its body about with the force and spite¬ 
ful ness it does when anything molests it, we should scarcely suppose any 
other creature would eare to encounter it. And yet it finds its mortal foe 
in a little four-winged fly, scarcely a thousandth part its size. It is truly 
wonderful that such a pigmy as is this fly is able to attack and destroy 
such an elephant as is this worm. The fly alights upon the worm, and with 
the short sting or ovipositor with which it is furnished pierces its skin and 
inserts a minute egg in the puncture. It continues to repeat this opera¬ 
tion at one point and another upon the back and sides of the wdrm, until 
its whole stock of eggs, amounting to a hundred or more, is exhausted. 
These eggs hatch minute maggots, which distribute themselves all through 
the body of the worm, feeding upon its fatty substance, but without attack¬ 
ing any of its vital parts. And thus the worm continues industriously to 
feed and elaborate nourishment for feasting and pampering these greedy 
parasites which are luxuriously rioting within it. If a worm which is thus 
infested be cut into, it appears to be everywhere filled with these little fat 
maggots. When they have got their growth they gnaw out through the 
skin, but instead of dropping to the ground and there secreting themselves 
as they would be expected to do, they still cling to the unfortunate worm, 
each maggot spinning for itself a little oval white cocoon, one end of which 
it fastens to the skin of the worm at the orifice where it has issued from 
it. Thus the worm comes to present the remarkable spectacle of being 
clothed, as it were, with a hundred or more of these cocoons, resembling 
Vttle white seeds like kernels of rice adhering to and in places wholly cov¬ 
ering its back and sides. I have counted one hundred and twenty-four of 
these cocoons upon a single worm, and a still larger number will probably 
be found in some instances. 
These parasitic cocoons arc milk white and of a regular oval form, 0.15 
long and 0.06 broad. Their walls are no thicker than thin writing paper, 
but are very dense and firm. Their surface is minutely uneven, with a few 
loose, wrinkled threads at one end, whereby they aro held to the skin of 
