structure. We have already cracked several such nuts, but many
remain to be opened. All such puzzling specimens are spread on
single sheets and set aside. . .But more of this when we are
together again. . .Dr. Leuckart begs you to study carefully the
"Hebammen Unke;"* (* Bombinator obstetricans referred to in a
former letter.) to notice whether the eggs are already fecundated
when they are in the earth, or whether they copulate later in the
water, or whether the young are hatched on land, and what is their
tadpole condition, etc. All this is still unknown. . .

AGASSIZ TO BRAUN.

ORBE, June 10, 1827.

. . .Last week I made a very pleasant excursion. You will remember
that I have often spoken to you of Pastor Mellet at Vallorbe, who
is much interested in the study of the six-legged insects. He
invited me to go to Vallorbe with him for some days, and I passed a
week there, spending my time most agreeably. We went daily on a
search after insects; the booty was especially rich in beetles and
butterflies. . .I examined also M. Mellet's own most excellent
collection of beetles and butterflies very carefully. He has many
beautiful things, but almost exclusively Swiss or French, with a
few from Brazil,--in all about 3,000 species. He gave me several,
and promises more in the autumn. . .He knows his beetles
thoroughly, and observes their habits, haunts, and changes (as far
as he can) admirably well. It is a pity though that while his
knowledge of species is so accurate, he knows nothing of
distribution, classification, or general relations. I tried to
convince him that he ought to collect snails, slugs, and other