A doctor from Zeeland, Angelus van Wijkhuysen, wrote Letter L-259 to request Leeuwenhoek's opinion on the origin of flies from a dead caterpillar
This letter is known only by reference in another letter.
The “doctor from Zeeland” is probably Angelus van Wijkhuysen, who visited Leeuwenhoek several times; presumably, most of their correspondence is lost. It is not known whether Leeuwenhoek sent the reply mentioned in Letter L-261 of 12 July 1695.
Wijkhuysen is also probably the “certain gentleman” who wrote Letter L-269 of a few months before September 1695.
Letter L-261 of 12 July 1695 to Maarten Etienne van Velden
A certain medical doctor also sends me from Zeeland such a small cocoon, from which small flies have also emerged, but he intended also to send me the shrivelled caterpillar from which they had emerged, but it had got lost. This gentleman also is not satisfied about the reproduction of these small flies and requests my opinion about it. When I reply to his letter, I will send him no other but my above-mentioned views.