Discusses factors possibly influencing the sex of caterpillars. Is gathering information on sex ratios in insects and would welcome any cases in which males seem to outnumber females.
Down. | Bromley. | Kent. S.E.
My dear M
Though you are so kind as to say that you will write again, I must thank you at once for your letter, which is of the highest value to me.— Your results are most curious, & show what caution is requisite. Do you think it possible that breeding very young caterpillars under confinement & therefore not under strictly natural conditions could influence the sex. I do not recollect how soon the sexual organs are differentiated in Larvæ. Perhaps Sir J. Lubbock may know. It has been stated (but I cannot say that I quite believe it) by Knight that heat will determine the sex in unisexual flowers.
I have had a note from M
I think I will write to D
I hope I shall not utterly weary you.—
With cordial thanks | Yours very sincerely | Ch. Darwin
- f1 5907.f1The year is established by the relationship between this letter and the letter from H. T. Stainton, 20 February 1868.
- f2 5907.f2See letter from H. T. Stainton, 20 February 1868.
- f3 5907.f3John Lubbock.
- f4 5907.f4CD refers to Thomas Andrew Knight. The statement alluded to has not been found in any publication by Knight.
- f5 5907.f5See letter from Roland Trimen, 20 February 1868 and n. 13.
- f6 5907.f6In Descent 1: 311, CD wrote: `It is well known that if a virgin Lasiocampa quercus or Saturnia carpini be exposed in a cage, vast numbers of males collect round her, and if confined in a room will even come down the chimney to her.'
- f7 5907.f7Alexander Wallace.
- f8 5907.f8CD obtained information on silk-moths from the Italian zoologist Giovanni Canestrini (see Descent 1: 309, 311).
- f9 5907.f9See letters from W. B. Tegetmeier, [before 15 February 1868] and nn. 4 and 5, and [16--20 February 1868] and n. 2.