Ɛpsilon

From Giovanni Canestrini1   13 March 1868

Museo | di Storia Naturale | della Regia Università | di | Modena | Modena

13 März 1868

Hochgeehrtester Herr,

Ich habe Ihr geehrtes Schreiben vom 2. März richtig erhalten und antworte in deutscher Sprache, da diese mir geläufiger ist als die englische und Ihnen wahrscheinlich verständlicher als die italiänische.—2 Ich muss mir einige Zeit gönnen, um die von Ihnen gewünschten Notizen zu sammeln. Mir vorbehaltend, in ein Paar Wochen Ihnen weitere Nachrichten zu geben, kann ich vorläufig folgendes sagen.

Es ist eine in Italien ausgemachte Sache, dass der Seindenwurm (Bombyx mori) eine grössere Anzahl von weiblichen als von männlichen Schmetterlingen giebt.3 Daher werden die Männchen mit grossem Fleisse und grosser Sorgfalt aufbewahrt, um damit mehr als ein Weibchen zu befruchten. Diess habe ich selbst sehr oft beobachtet und mehrere befragte erfahrene Seidenwurmzüchter haben es vollkommen bestätigt. Einige Züchter fügten hinzu, es habe sich dieses Missverhältniss bedeutend gesteigert durch die Krankheit, welcher der Seidenwurm seit vielen Jahren ausgesetzt ist.4 Auch habe ich (und andere) beobachtet, dass das Weibchen von der Krankheit mehr als das Männchen befallen ist.

Seit einigen Jahren wird hir auch der Aïlantus Wurm (Bombyx cinthia) gezogen und kann man jährlich zwei Generationen haben.5 Die Schmetterlinge der ersten Generation sind vorwaltend Männchen, die der zweiten Generation Männchen und Weibchen fast in gleicher Zahl oder etwas vorwaltend Weibchen. Indess ist hier zu bemerken, dass die Raupen der ersten Generation sich in der Zeit entwickeln wo die Wespen sehr zahlreich sind und von diesen vertilgt werden, und einige Züchter annehmen, mit mehr oder weniger Grund, dass die Wespen eine Vorliebe für die weiblichen Schmetterlinge haben könnten, wodurch das Missverhältniss gesteigert würde. Genaure Beobachtungen liegen darüber bis jetzt nicht vor.

Hinsichtlich der wildlebenden Thiere bemerke ich dass der Fisch Cobitis taenia, bei uns sehr häufig, nur in weiblichen Exemplaren beobachtet wurde, was schon prof. De-Filippi beobachtete und und auch ich bestätigt habe.6 Man hat einen ähnlichen Fall wie beim Aal.

Ueber Bellingieri’s Arbeiten werde ich Nachsuchungen machen; seine Arbeiten wurden in den Acten der Turiner Akademie veröffentlicht, vielleicht findet man Sonderabdrücke.7

Mit aller Hochachtung | Ihr ergebenster | Prof. Joh. Canestrini.

CD annotations

2.1 Es ist … Sache, ] underl pencil
2.2 Daher … beobachtet, 2.5] scored blue crayon
2.4 um … befruchten.] underl pencil; scored red crayon
2.6 Einige … befallen ist. 2.9] scored blue crayon
2.8 Auch … befallen ist. 2.9] double scored ink
3.1 Seit … Weibchen. 3.4] crossed ink
3.2 jährlich] underl blue crayon
3.6 einige Züchter … würde. 3.9] scored red crayon; double scored pencil; ‘(Not sufficiently proved)’ added ink
3.9 Genauere … bestätigt habe. 4.3] scored red crayon
1
For a translation of this letter, see Correspondence vol. 16, Appendix I.
2
CD’s letter has not been found.
3
Earlier, CD had received information suggesting that there were an almost equal number of male and female Bombyx mori (the common silkworm) produced (see letter from Armand de Quatrefages, 4 March 1868).
4
Canestrini probably refers to pébrine, the silkworm disease, the effects of which were catastrophic to the silk industry in the Mediterranean region in the 1850s and 1860s (see Federico 1997, pp. 36–9).
5
The reference is to Bombyx cynthia (now Samia cynthia, the ailanthus silkworm; so named because it feeds on leaves of Ailanthus altissima). For more on the number of generations of different silkworms, see Riley 1886, p. 15.
6
Filippo De Filippi reported observations on Cobitis taenia, the spined loach, at a meeting of the Italian society for natural science in 1865; he referred to the fish by a now unaccepted synonym, Acanthopsis taenia (see Atti della Società Italiana di Scienze Naturali 8 (1865): 265). See also Canestrini’s critical outline of Italian freshwater fishes (Canestrini 1866).
7
CD had evidently asked about obtaining works by Carlo Francesco Bellingeri. CD had cited information on the gestation and fertility of dogs from French accounts of Bellingeri’s work in Variation 1: 30, 2: 112. CD may have inquired about Bellingeri’s research on the proportion of sexes in mammals and birds. Only a brief summary was published in Memorie della Reale Academia delle Scienza di Torino 2d. ser. 4 (1842): xlvi–xlvii. For the complete work, see Bellingeri 1840.

From Giovanni Canestrini1   13 March 1868

Museo | Di Storia Naturale | Della Regia Università | di | Modena | Modena

13 March 1868

Highly Honoured Sir,

I have received your honoured letter of 2 March and reply in German, for I am more fluent in it than in English, and you will most probably understand it better than Italian.—2 I must allow myself some time to collect all the information you wanted. With the proviso of giving more information in a couple of weeks’ time, I can tell you the following for the present.

In Italy it is an established fact that the silkworm (Bombyx mori) produces a larger number of female than of male butterflies.3 The males are therefore looked after with great diligence and great care, so that each can fertilise more than one female. I myself have often observed this and a number of experienced silkworm-breeders have absolutely confirmed it. A few breeders added that this imbalance has significantly increased as a result of the disease to which the silkworm has been exposed for a number of years.4 Also, I (and others) have observed that this disease affects the female more than the male.

For a number of years we have also produced the ailanthus worm (Bombyx cinthia), and two generations can be raised per year.5 The butterflies of the first generation are predominantly male, those of the second generation males and females in equal proportion, or slightly more females than males. It must however be noted that caterpillars of the first generation develop at a time when wasps are abundant, and are destroyed by them, and a number of breeders assume, with more or less reason, that the wasps might have a preference for female butterflies, which would increase the imbalance further. More detailed observations on this are not as yet available.

With respect to wild animals, I notice that only the female of the fish Cobitis taenia, which is very common here, has been observed, which has already been noted by prof. De-Filippi and also confirmed by me.6 The case is similar to that of the eel.

I shall make enquiries about Bellingieri’s works; his papers were published in the Acts of the Academy of Turin, and possibly offprints are available.7

With all my respects | Your most devoted | Prof. Joh. Canestrini.

1
For a transcription of this letter in its original German, see part I: 264.
2
CD’s letter has not been found.
3
Earlier, CD had received information suggesting that there were an almost equal number of male and female Bombyx mori (the common silkworm) produced (see letter from Armand de Quatrefages, 4 March 1868).
4
Canestrini probably refers to pébrine, the silkworm disease, the effects of which were catastrophic to the silk industry in the Mediterranean region in the 1850s and 1860s (see Federico 1997, pp. 36–9).
5
The reference is to Bombyx cynthia (now Samia cynthia, the ailanthus silkworm; so named because it feeds on leaves of Ailanthus altissima). For more on the number of generations of different silkworms, see Riley 1886, p. 15.
6
Filippo De Filippi reported observations on Cobitis taenia, the spined loach, at a meeting of the Italian society for natural science in 1865; he referred to the fish by a now unaccepted synonym, Acanthopsis taenia (see Atti della Società Italiana di Scienze Naturali 8 (1865): 265). See also Canestrini’s critical outline of Italian freshwater fishes (Canestrini 1866).
7
CD had evidently asked about obtaining works by Carlo Francesco Bellingeri. CD had cited information on the gestation and fertility of dogs from French accounts of Bellingeri’s work in Variation 1: 30, 2: 112. CD may have inquired about Bellingeri’s research on the proportion of sexes in mammals and birds. Only a brief summary was published in Memorie della Reale Academia delle Scienza di Torino 2d. ser. 4 (1842): xlvi–xlvii. For the complete work, see Bellingeri 1840.

Please cite as “DCP-LETT-6010,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-6010