20 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
Grote's paper before the American Association for the Advancement of 
Science, in 1874, we shall give somewhat in detail in Chapter XIV, but 
in this connection we may appropriately devote a brief space to the 
consideration of Mr. G rote's arguments: 20 
The principal arguments urged in support of the theory by Mr. Grote 
are [1] the sudden appearance of the moth in quantities; [2] the first 
appearance of the worms so late as the latter part of June; [3j the 
absence of parasitic checks; [4] the highly probable exotic origin of the 
species and its introduction into the States; and [5] the power of flight 
and migratory habits of the moth. The first three lose much of their 
force from the facts adduced in this report, since [1J in the southern 
portion of the belt 21 the sudden appearance is more apparent than real; 
[2] the worms appear in April;* and [3] they have numerous parasitic 
checks. There is also little force in the fact of original introduction 
from some foreign country, since most of our worst insect pests that are 
now acclimated and established with us were originally introduced from 
abroad; while [5] the migratory habit, as we have seen, is not developed 
in the first moths. Arguments urged by others in favor of the theory 
are [G] the periodical visitations and intervals of immunity; [7] the short 
life of the moth; and [8] the failure of those who have tried to keep it 
through the winter. 
To these it may be replied that [6] many other indigenous insects 
abound during certain years and are unknown in others, and that these 
changes are due to the working of well-known laws; that periodicity in 
the appearance of Aletia is largely imaginary, because it either refers 
only to bad years and takes no stock of small numbers, or else is local. 
The investigations of the Commission show that the worm has been in 
some parts of the South ever since the civil war, and there is no reason to 
suppose that it was not annually to be found in fewer or larger numbers 
prior thereto. [7] The short life of the moth of the summer generations 
is no criterion for that of the last or hibernating brood, since any num- 
ber of species which produce several annual generations and have but a 
brief span of life in the imago state in summer are known to hibernate in 
this state. [8] Itis extremely difficult to attain, in a room, the proper con- 
ditions of moisture and freshness that belong to a sylvan atmosphere, and 
we have never been able to keep other Lepidoptera which hibernate in 
the imago state alive through the whole winter in such artificial situation, 
though we have tried with both Danais archippus and Paphia glycerium. 
For this reason it will always be next to impossible to get absolute and 
incontrovertible proof of the hibernation of Aletia by watching the mot lis 
from fall till they oviposit in the following year, but it may be truly said 
that if the hibernation of other species rested on equally absolute proof, 
there is not one among the Lepidoptera, or other Orders, for that matter, 
that could be said to hibernate. One other argument that has been 
made in favor of the theory may lastly be mentioned. It is that during 
the late war no cotton was grown for three years in some sections of the 
* See farther facts in Note 12. 
