Page:The spiders of the northern states-1901.djvu/10

 a similar net, but places it horizontally, or slanting. The spiral thread is curly and differently put on.

The identification of spiders offers many diffculties. The individuals often vary in color and size.

The males are sometimes not half the size of the females, and differ from them in color and markings.

The markings are often faint and differ in various moultings. The scientific distinctions are based on the

sexual organs; the end knob of the feelers of the male; the number of claws on their feet,—all, objects too minute to serve as distinctions to the every-day observer.

The eyes and their position form the principal means of finding the families. placed in each kind. raised on warts.

They are differently Some kinds have large and small eyes, others have several protruding eyes, as if

The grouping is important, also, as some of the species have all their eyes in a close bunch, or a pair, while others have them scattered far apart.

The student must observe the eyes from full front view, and must notice whether they are placed in two or three horizontal rows, also, whether these rows are straight, curved upwards, or bent downwards.

GaN sie

OG S O. wae 70 °2.9° ri cae oe 4 00 8 Seat See, 22 sae ——" Attus. Lycosa. Dolomedes. Agalena. Epeira.

Observe that in Avs the large eyes are in the lower row, while in Lycosa the small eyes are in this position.

In Atius the rows curve upwards; in Lycosa they are straight; in Aga/ena they are bent down- wards.

The difference between Lycosa and Dolomedes is,—in the first, the four large eyes form almost a square; in the second, the two eyes of the upper row are far apart.

In Epeiva the two eyes on each side are close together.

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