106 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
valuable and interesting. He concludes that when the adult male is 
more conspicuous than the adult female, the young of both sexes 
Peok- closely resemble the latter in form and color. On the contrary, 
roar ae when the female is more conspicuous the young follow the more 
Attide, modest colors of the male, especially in the earlier moults. 
When the adult sexes resemble one another the young of both 
sexes favor the common type. 
As examples of the above, Phidippus johnsonii female has the abdomen 
red and black, with a white base and some white dots; the male is bright 
vermilion red, with sometimes a white band at the base. The young of 
both sexes resemble the less showy mother until the last moult, when the 
males assume their bright livery. 
In another species, Habrocestum splendens, which the Peckhams illus- 
trate with a good plate, the young during the first moults more closely 
resemble the female, which is the less showy sex. The male is a brilliant 
fellow, who dons his gorgeous livery at the last moult just as he becomes 
mature, though in some species the nuptial robe is acquired one moult 
before maturity. 
Among the Laterigrades the same rule obtains, several species of 
Thomisids showing greater brilliancy of color among the adult males, 
while the young males resemble the female until the last moult. 
In Sparassus smaragdalus! the female has a deep green body and 
legs of somewhat lighter shade; the male? has green corselet and 
legs, but the entire dorsum of the abdomen yellow, with a wide herring 
bone median stripe of red and the folium margined on each side with the 
same color. The young at the first moult are a 
dull whity-yellow color and grayish legs, but in 
subsequent moults are said to resemble the mother. 
Figs. 65 and 66 will illustrate the difference 
resulting from the final moult of male spiders 
generally. The drawings are made from a male 
Zilla atrica, Fig. 65 being the form shortly before 
the last moult and Fig. 66 that of the mature 
male. In some species the difference between ma- 
Fic. 65. Immature male palp of ‘Ure and immature palps is much more striking. 
Zilla atrica, Fic. 66. The same It is not correct to say that these modifica- 
je eras tions are effected in the interval of the last moult 
alone. In point of fact the distinctions begin to appear earlier, but they 
are commonly so difficult to detect, and the apparent change effected during 
Lateri- 
grades. 
Fic. 65. Fia. 66. 
‘A fine female of this species with her cocoon and young was taken by Rey. W. F. 
Anderson, of Fordham, N. Y., on the mountains of Switzerland and brought to America 
safely. It was sent to me alive and lived several weeks. The young were all a dull yellow- 
ish color with livid legs, but I could not preserve them beyond the first moult. 
* Blackwall, Spiders Gt, B. & I., Vol. IL, pl. v., Fig. 61. 
a 
