16 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
As partly illustrating this difficulty it will bo well to elaborate the 
statements made in a paper read by the writer before the National 
Academy of Science at its meeting in Washington in the spring of 1879. 
There are three principal theories on the subject that are worthy of 
consideration, and that are held by those with whom Ave have come in 
contact, or with whom we have corresponded. These are: 
1st. That it hibernates in the chrysalis state. 
2d. That it hibernates as a moth. 
3d. That it does not hibernate in any part of our cotton-growing 
States, but comes into them on the wing from warmer climates where 
the cotton-plant is perennial. 
Some few persons think that it winters in the egg state in cotton- 
seed or on the dead stalk of the plant ; but such views may be disposed 
of by the statement that they are unsupported by even the appearance 
of fact. 
At first blush it would seem easy enough to dispel whichever of these 
theories is erroneous and settle the question under consideration by a 
few simple facts of observation. The trouble is, however, to get at the 
facts. 
About one-fourth of the intelligent people of the South hold the opin- 
ion that this Aletia hibernates in the chrysalis state, some believing that 
it does so above ground, others that it retreats beneath the surface of 
the ground. It has generally been stated by the writers on this insect 
that the chrysalis could not endure the slightest frost. We have been 
able to prove that it will suffer with impunity a temperature of from five 
to ten degrees below the freezing point, but that it cannot withstand a 
lower temperature; and all those chrysalides which do not give out the 
moth before severe cold weather sets in perish beyond any doubt. ITow 
easily men are misled even on this point, however, may be gathered from 
the fact that Dr. Anderson kept what he believed to be living specimens 
until after the severe cold of December. A careful examination proved 
that the lifelike motions of such chrysalides were due to the living pupa 
which they contained of one of the parasites (Pimpla conquisitor) pres- 
ently to be described. The larger proportion of chrysalides that are 
not empty after a severe frost has occurred are infested with some kind 
of parasite, though many of them ha ve perished from the effects of the 
frost and are either rotten or moldy. 
Any number of intelligent planters insist that they plow up the 
chrysalides in spring, and the belief that the last brood works beneath 
the ground, out of reach of frost, is very firmly held by some of the 
most experienced cotton growers; but in every instance that has come 
to our knowledge the chrysalides thus plowed up have proved to be- 
long to other species, most of them of the same family, and many of 
them having a sufficiently close resemblance to those of Aletia to con- 
found any but the most skilled and experienced entomologist. As an 
illustration of the ease with which erroneous conclusions can be drawn 
