Summary

Thanks for interesting letter which confirms belief that a good observer is a good theorist.

He is glad to hear that HWB, with his wide knowledge of natural history, has anticipated CD in many respects and agrees with the Origin.

Has been thoroughly attacked, especially by entomologists – J. O. Westwood, T. V. Wollaston, and Andrew Murray.

Glad HWB is writing on "equatorial refrigeration"; CD expresses his belief in north to south migration during glacial period.