Now Mr. Spence Bate informs me that in most of the crustacean orders, especially in the highest or the brachyura, the male is larger than the female; the parasitic genera, however, in which the sexes follow different habits of life, and most of the Entomostraca must be excepted.
"The Descent of Man and Selection in Relation to Sex, Vol. I (1st edition)"
Charles Darwin