CARBONIFEROUS ARTHROPOD FA UNA 1 9 1 



Petromartus gen. nov.' 



Head small, with prominent mandibles. Prothorax elongate ; 

 meso- and metathorax quadrate. Abdomen stout, tapering beyond 

 the middle and provided with prominent sexual organs on the 

 antepenultimate ventral segment. Legs rather stout. Wings long, 

 exceedingly slender, rather triangular in outline, broadest at the 

 beginning of the outermost third where the hind margin forms 

 an obtuse angle ; neuration simple, nearly straight ; mediastinal 

 vein long; scapular simple, unbranched. Externomedian several 

 times branched ; internomedian of similar formation. All the 

 veins extend straight from the narrow base and evenly fill out 

 the apical portion of the wing with a gentle curvature. Num- 

 erous well-marked and distant transverse cross-veins connect 

 the longitudinal veins. Underwings similar, but probably broader. 

 Wings overlapping the abdomen when at rest. 



18. Petromartus indistinctus sp. nov. (Plate VI, Fig. 6; Plate VII, Figs. 

 12, 13). 



Male. — Elongate slender insect with thickened abdomen, 

 and very narrow fore wings. Head quadrate, longer than broad; 

 mandibles prominent. Prothorax slender, elongate, provided 

 with a transverse sulcus in front of the middle; sides and pos- 

 terior edge margined. Mesothorax broader, rectangular, bear- 

 ing the fore wings at the hind angles. Remainder of thorax and 

 base of abdomen obscured. Abdomen broad, elongate, consist- 

 ing of ten segments, including the mediary segment, which is 

 supposedly present. At the eighth segment is a large and broad 

 ventral tubercle bearing a pair of clasping valves which meet in 

 a mid-longitudinal line. The sexual apparatus of the last seg- 

 ments and the caudal appendages are obliterated. Legs imper- 

 fectly preserved ; femora compressed, their sides flat, twisted in 

 position as described for the other species. Front wings more 

 slender than the hind ones and comparatively smaller ; veins 

 straight, connected by numerous strong cross-veins ; venation 

 reconstructed as follows : mediastinal vein extending two-thirds to 

 the wing-tip; scapular vein straight, parallel with the mediastinal, 

 and connected with it by numerous transverse veins. These cross- 



'^■trirpos, "a stone;" fidprv^, "a witness." 



