20 ■ PECKHAM. [Vol. 1. 



females, and that the same is true, with a few exceptions, in the 

 individual collections. Excepting when the spiders are well- 

 known, as in the case of Simon's Attidx of France, a compari- 

 son of the description of the two sexes, when they have been 

 put together, would only serve to show a similarity between the 

 males and females, since it would be only in the species where 

 there was little or no sexual difference that they could be placed 

 together. Where they are well-known, as in the Attidse of 

 France, we find by sucli a comparison that in thirty-nine species 

 the male is plainly unlike the female, being in twenty-six in- 

 stances much more conspicuous, while in fifty-five the sexes are 

 similar, or, if they differ, the male is no more conspicuous than 

 the female. These facts are given to make it clear that the 

 sexes very commonly differ, the male being brighter than the 

 female. It is probably not too much to saj"-, that in the Attidse, 

 at least two-fifths of all the species have the male more conspic- 

 uous than the female. 



Menge^, in referring to the greater brilliancy of the male of 

 Micromata omata, says that it only assumes its bright color as 

 a " bridal adornment," and in this connection makes the state- 

 ment that in the families Thomisidse and Scdticidse the males are 

 generally more beautifully colored than the females. We have, 

 in North America, several Thornisidie that are like Menge's 

 species in the difference in color between the sexes, and also in 

 that the young males are like the female, and only assume 

 their bright color at the last moult. Darwin remarks on the 

 fact that " the female of Sparassus S7naragdulus is dullish green, 

 whilst the adult male has the abdomen of a fine yellow, with 

 three longitudinal stripes of rich red ;" while young this male 

 resembles the female. The obvious conclusion from these facts 

 is that it is the male that has varied, and this, too,' late in life, 

 so that his peculiarities, having been limited to one sex, do not 

 appear in the young. We are not embarrassed in this group 

 by any need on the part of the female for plain colors to pro- 

 tect her during incubation, since, without exception, the cocoon 



1 Preiissische Spimien, II, p. 396. 



