Sends his paper on "Willow-galls" [Proc. Entomol. Soc. Philadelphia 3 (1864): 543–644].

Lengthy criticism of Agassiz’s views on species as stated in his Essay on classification [1857].

Interested by CD’s trimorphism in Lythrum. Thinks some great mystery may lie in the fact that in some genera, some species are tri-, some di-, and some monomorphic, and in other genera, Apis, Vespa, Bombus, all the known species are dimorphic.

Discusses several subjects, including examples of "Unity of coloration",

the origin of gall-producing poison,

Wagner’s theory of viviparous larvae,

and stridulation in insects.

Sends a reference supporting CD’s statement in Origin that flies check propagation of horses and cattle.

Acknowledges CD’s paper on "Climbing plants".

Mentions Asa Gray’s complimentary notice in Silliman’s Journal [Am. J. Sci. and Arts 2d ser. 40 (1865): 273–82].

His difficulty in understanding how males of Daphnia or any other genus can produce eggs. If there is no impregnation, how can there be sexual organs? Why call one form male and another female?

He has sent CD his paper on "the new Potato Bug".

Will soon send "On Phytophagi Species & Unity of Coloration". [phytophagic!?]

Complaints about practices of the English Post Office.

His current research and description of the rationale of his experiments.