366 Wisconsin Academy of Sciences, Arts and Letters. 
Cephalo thorax rather low, twice as long as wide, rounded and 
narrower behind. There is a deep constriction near the middle 
of the thoracic part and also in the middle of the abdomen. 
Quadrangle of eyes but little wider than long, a little wider be¬ 
hind than in front, occupying one-third of the cephalothorax. 
Anterior eyes in a curved row, middle eyes touching and very 
large, two and one-half to three times as large as the lateral, 
which are a little separated from them. Second row a little 
nearer the first than the third row. Dorsal eyes a little larger 
than the lateral. Lip about as wide as long. Falces with sev¬ 
eral teeth on lower border. 
The spiders in this genus are the most ant-like of all our 
spiders, and are not easily distinguished from ants, even by a 
naturalist. 
SYNEMOSYNA FORMICA H. 
Plate L, figures 1—1c. 
1845. Synemosyna formica H., Jour. Bost. Soc. Nat. Hist., V. 
1846. Janus gibberosus C. K., Die Arachniden, XIII, p. 21. 
1875. Synemosyna formica H., Occ. Pap. Bost. Soc. Nat. Hist., II, p. 73. 
1883. Synemosyna formica P., Descr. New or little known Attid® of 
U. S., p. 30. 
1888. Synemosyna formica P., Wis. Acad. Scineces, Arts and Letters 
VII, N. A. Att., p. 93. 
1891. Synemosyna formica E., Trans. Conn. Acad., VIII, p. 30. 
1892. Synemosyna formica P., Occ. Pap. Nat. Hist. Soc. Wis., II, pt. 1, 
p. 77. 
1892. Synemosyna formica B., Proc. Acad. Nat. Soc. Phila., p. 80. 
Length, $ 3.9 mm., 9 5.4 mm. Legs in both sexes 4312; 
equally stout. The middle eyes of the first row are three times 
as large as the lateral; the other eyes are small. The anterior 
end of the abdomen has the integument hardened in the middle 
and has also a hard piece on the under surface, which extends 
upward on each side so that the edges are visible from above. 
The posterior end of the abdomen is widened and rounded. 
The falces are short and vertical in the female, and a little 
longer, and curved apart in the middle in the male. The color 
