86 



Alexander Pelruukevitch. 



pair of tracheal tubes, or tracheal tubes absent, or two pairs of 

 tracheal tubes and no lungs 



Arachnomorphae 



LIST OF DESCRIBED SPECIES OF ARAXEAE 

 Sub-Order Mesothelae. 

 Abdomen segmented. Four pairs of spinnerets in the middle of 

 the abdomen on its ventral surface. Two pairs of lungs. Chelicera 



Fig- 52. 



Fig. 51- 



Figure ^i. — Liphistius fi?esM//oy Schiodte fromPinang; dorsal view. Figure 52. — 

 Same, ventral surface. (From Encyclopaedia Britannica, nth ed.) 



so articulated that the fangs move in a plane parallel to the plane of 

 symmetry. 



Family Arthrolycosidae Fritsch. 

 Genus Arthrolycosa Harger. 

 Genotype A. antiqua Harger. 

 I. Arthrolycosa antiqua Harger, Amer. Jour. Sci., (3), Vol. VH, 1874, 

 pp. 219—223. Beecher, Ibid., Vol. XXXVHI, 1889, p. 219—223, 

 figs. 1-3. 



From the Pennsylvanic (Lower Allegheny) of Mazon Creek, 

 IlHnois. 



