Agalenidm and Dysderidm. 169 



tion another species, Geotrecha hivittata, is named by Keyserling 

 Gastlaneira hiinttata, the genus Castianeira having been named by 

 Keyserling, in 1879, for a South American spider, with a long, 

 slender cephalothorax and a slender abdomen with the front part 

 hardened and differently colored from the softer part. 



In our species of Geotrecha, the cephalothorax is about two-thirds 

 as wide as long and narrowed in front, more in some species than in 

 others. The abdomen is longer and a little wider than the cephalo- 

 thorax. It sometimes has a small, hard patch at the front end which 

 is of the same color as the rest of the back and not easilj'^ seen. The 

 abdomen is round, not flattened above as it usually is in Prosthesima. 

 The legs are long and slender. The hairs on the under side of the 

 first and second legs are only slightly flattened and thickened, and the 

 claws concealed by a thick bunch of hairs. The maxillae are nearly 

 sti'aight as in Agroeca and the labium is as short as wide. The eyes 

 are close together in the middle of the front of the head, the front 

 row nearly straight and the hind row with the middle eyes highest. 

 The middle eyes of both rows are largest and farther apart than 

 they are from the lateral eyes. The spinnerets are very small and 

 close together. The colors are dark brown and black, with white or 

 bright colored markings. 



The male palpi have the patella and tibia both short and the tarsus 

 long and tapering. The palpal organ is round at the base and tajjers 

 to a fine point. The epigynum has two simple openings dii'ected 

 backward, and differing in size and distance apart in different species. 



G-eotrecha bivittata. 



Castianeira bivitkita Keyserling, specimens in Cambridge Museum. 

 Plate III, figures 3a, 36, 3c, 3d. 



Length, 7 or 8"'™. Legs of fourth pair, 10 or 11™'". The cepha- 

 lothorax is widest across the middle in front of the dorsal groove, 

 Plate III, fig. 3a, and is about half as wide at either the front or 

 hinder end. The abdomen is usually about as long as the cephalo- 

 thorax and widest at the hinder third. It is sometimes slightly 

 drawn in at the sides and above over the front white marking. This 

 is caused by contraction in alcohol, the front end of the abdomen 

 being hardest contracts less than that part just behind it. The legs 

 are long and tapering, the fourth pair longest. 



The cephalothorax is dark brown. The abdomen is of the same 

 color, a little lighter, with two white cross stripes, one about the 

 middle of the back and the other, a less distinct one, farther for- 



