THE AMERICAN ENTOMOLOGIST. 



late years I permit the White Pine Weevil 

 to have its own way among my spruces, 

 merely limiting the number at work among 

 the small stock in nursery rows. — A. S. F. 



ON THE HIBERNATION OF THE COTTON WORM.* 



Aletia argillacea Hiibn. 



No question connected with the Cotton 

 Worm has given rise to more speculation 

 than that of the hibernation of the insect, 

 and this fact at once finds its explanation 

 in the difticulty that surrounds the subject. 

 As partly illustrating this difficulty it will 

 be well to elaborate the statements in a 

 paper read by the writer before the Na- 

 tional Academy of Science at its meeting 

 in Washington last spring. There are three 

 principal theories on the subject that are 

 worthy of consideration, and that are held 

 by those with whom I have come in contact 

 or with whom I have corresponded. These 

 are : — 



ist. — That it hibernates in the chrysalis 

 state. 



2nd. — 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 pe- 

 rennial. 



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 appear- 

 ance of fact. 



At first blush it would seem easy enough 

 to dispel whichever of these theories is er- 

 roneous and settle the question under con- 

 sideration by a few simple facts of observa- 

 tion. The trouble is, however, to get at 

 the facts. 



About one fourth of the intelligent peo- 

 ple of the South hold the opinion 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 chrys- 



* From advance sheets of Bulletin 3 of the U. S. Entomolo- 

 gical Commission, by C. V. Riley. 



alis could not endure the slightest frost. 

 I 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 tem- 

 perature ; and all those chrysalids which 

 do not give out the moth, before severe 

 cold weather sets in, perish beyond any 

 doubt. How easily men are misled even 

 on this point, however, may be gathered 

 from the fact that Dr. E. H. Anderson of 

 Kirkwood, Miss., a most intelligent ob- 

 server and experienced cotton planter, kept 

 what he believed to be living specimens 

 until after the severe cold of December 

 1878. A careful examination proved that 

 the life-like motions of such chrysalides 

 were due to the living pupa which they 

 contained of one of the parasites {Pimpla 

 conquisUor) presently to be described. The 

 larger proportion of chrysalides that are 

 not empty after a severe frost has occur- 

 red, are infested with some kind of par- 



[Fig. 3.] 



Aletia argillacea : «, moth wings expanded ; b, do. wings 

 closed and head downward (after Riley). 



asite, though many of them have perished 

 from the effects of the frost and are either 

 rotten or moldy. Any number of intelli- 

 gent 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 grow- 

 ers ; but, in every instance that has come to 

 my knowledge, the chrysalides thus plowed 

 up have proved to belong to other species, 

 most of them of the same family, and many 

 of them having a sufficiently close resem- 

 blance to those of Aletia to confound any 

 but the most skilled and experienced ento- 

 mologist. As an illustration of the ease 

 with which erroneous conclusions can be 

 drawn from mistaken identity, I will here 

 quote part of a letter received last Spring 



