258 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
species. He retained my name, deeming the two spiders distinct. Not having seen a 
European specimen, I retain the name originally given, as above, although inclined to 
think, from study of the drawings alone, Th. radiosum and Th. gemmosum identical, or 
perhaps the former a variety of the latter. 
Crpnatornorax: Cordate, truncate and indented at the base; the summit high; the 
head much eleyated, the face projecting in front, and wide; the fosse a slight semicircular 
indentation; sloping downward to the base and forward to the face; the corselet grooves 
distinct, as is the cephalic suture; the color dull yellow, glossy. The sternum is cordate, 
obtusely triangular at the apex; color dark brown, with a broad, yellow median band ; 
pubescent; rounded from the sides and flat in the middle; the Jabium small, scarcely more 
than one-third the height of the maxille, rounded at the tips; the maxille as wide as, or 
wider, than long; the tips squarely truncate, and inclined toward one another. 
Eyrs: (Fig. 8d.) Situated on a round, black conical projection, at the point of which 
the midfront eyes of the ocular quad are placed; the quad longer than wide, its greatest 
width behind; MF, which are considerably smaller than MR, are separated by about 1 to 
1.3 diameter; MR separated by scarcely more than a radius; the side eyes are separated 
by less than a radius; white, not greatly differing in size, but MR somewhat larger; SF 
removed from MF by a space almost equal to the area of the latter, or twice the inter- 
vening space or more; the clypeus is high, the margin separated from MF by 1.3 at least 
the area of the latter; the front row is aligned, or a very little recurved; the mear row 
procurved. 
Leas: 1, 2, 4, 3; short, rather stout; scantily pubescent; provided with sharp, bristle- 
like spines; the palps colored and armed as the legs; the mandibles long, conical, divergent 
at the tips, glossy, yellow. 
Anpomen: A rounded oval; the dorsum highly and eyenly arched, almost a semicircle, 
to the distal spinnerets; carried by the spider in a nearly vertical position, and, therefore, 
the base, which is rounded, towering over the cephalothorax ; the color varies from blackish 
to yellowish brown (Figs. 8, 8b); the skin soft, beautifully reticulated ; the folium a some- 
what indistinct, broad, arrowhead pattern, marked out by silvery reticulations, which give 
the spider a shining appearance. The epigynum (Fig. 8e) is large, occupying half the width 
of the yenter, with a high, subtriangular atriolum, showing the concavity beneath ; there is 
no scapus, simply a swelling at the middle point of the atriolum. 
Maz: (Fig. 9.) Resembles the female in color and markings; somewhat smaller in 
size; the palps are distinguished as shown at Figs. 9b, 9c, 9d. 
Disrrisutron: I haye collected this species in New England (Massachusetts, Connecti- 
cut); in New York, quite abundantly in the neighborhood of Philadelphia, and as far west 
as Ohio. Dr. Marx has it from Illinois. If we accept the identity of Theridiosoma 
gemmosum with the American species, it is widely distributed throughout Europe. 
Genus TETRAGNATHA, WALCKENAER, 1806. 
The species of this genus are distinguished by their elongated form, the abdomen 
being several times as long as wide. This effect is increased by the habit of the species to 
stretch their forelegs together and lie close to the surface of plants, so that the legs and 
abdomen form one continuous line. The cephalothorax is an elongated oval, flattened 
upon the dorsum of the corselet; the head usually erect, wide at the face, and quadrate. 
The sternum is longer than wide; and the maxillz peculiar, in that they are decidedly 
longer than wide, concave upon the outer margin, and widened at the tip. The eyes are 
placed in two rows, both of which are usually slightly recurved or aligned. The midfront 
eyes are separated from one another by a space ordinarily equal to about one-half the 
distance between the midfront and sidefront eyes; the side eyes are nearer one another than 
or as near as MF to MR. The mandibles are elongated, oval, usually narrower at the 
base than at the apex; are marked by strong teeth, and in the male are eyen more 
