LIMENITIS I. 
In relating the history of Melitsea Phaeton, I have shown how caterpillars work 
in community for protection against the winter. In the present case we see the 
individual taking care for itself, and with what forethought, mechanical skill, and 
patience the end is secured. Some caterpillars cover themselves in a web, or 
bind two leaves together loosely; more conceal themselves under wood and stone, 
or in the sod; but here is one who has turned tailor, weaver, and house-builder. 
It knows just what sort of leaf to choose for its purpose, takes its own measure¬ 
ment, cuts out the pattern on a system peculiar but effective, sows it up, and 
inserts an elastic silk band which will be its security when the drying leaf con¬ 
tracts, upholsters the interior, binds the stem of the leaf firmly to the branch, 
and takes possession, even having provided against the ingress of water by a flap 
shaped when the pattern was cut out. One cannot but wonder how such a habit 
originated and how it is perpetuated. Young birds are supposed to make obser¬ 
vations on the nest they were fledged in, and so prepare themselves to build a 
similar one when the proper time comes; but this caterpillar never saw anything 
like its winter house, and the butterfly which laid the egg from which the cater¬ 
pillars came knew nothing of houses. In the event of there being a summer 
as well as a fall brood of one of these case-making species, as in the southern 
Dis^ms and Ursula, the larvae of the early broods need no shelter, as they 
take no rest, but proceed through all the larval stages to maturity and to chrys¬ 
alis, and this habit of house-building manifests itself, therefore, only in the alter¬ 
nate generations. Nothing in the life-history of a butterfly seems more won¬ 
derful than that the egg should invariably be laid on the food plant proper to 
its caterpillar; for very few caterpillars are omnivorous, but nearly all will feed 
on two or three, and often on one species only of plant, and if they do not 
find the right plant they die of hunger. It would seem as if the butterfly has 
a remembrance of her former caterpillar state. Now she is as different as pos¬ 
sible, a creature of the sun and air, eating no solid food, for she has no mouth, 
but lives on liquids drawn up through a tube ; then she was a crawling worm, 
and voraciously fed on leaves, cutting them with powerful jaws. And between 
these stages there has intervened another that would seem to have divided them 
completely, certainly to have extinguished all recollections in the butterfty. 
And yet she seeks the particular plant her caterpillar must feed on, and finds it. 1 
1 At Coalburgh the larvte of Disippus feed on willow, and no aspen grows in this part of the State. In the 
Catskills, both willows and aspens abound, and there this species prefers to feed on the latter. I Lave often 
found their cases on young aspens late in the fall, but never on willow, though willow would be used if there 
was no choice. In 1876, I brought several small aspens to Coalburgh and planted, and since that time I find 
many larvm of Disippus feeding on the leaves; but on the willows near by, on which I had been accustomed 
to find them, I rarely have met one. Here was a case where perhaps for hundreds of generations neither 
caterpillar nor butterfly could have seen an aspen, but the moment One was produced the butterfly knew what 
would suit the caterpillar best, and deserted the willow. 
