ON SOME RARE ARACHNIDS 75 



Trithyreus Bagnallii, sp. nov. 



Length. — An adult female measured 3'i mm. exclusive of 

 the flagellum. 



Colour. — The tergites of the caput, thorax, and abdomen 

 are of a rich, shining dark brown, and have a slightly granular 

 surface. The first abdominal tergite, however, is an excep- 

 tion, being very pale and difficult to see. The 8th and 9th 

 abdominal sternites are almost as dark as the tergites, but all 

 the other sternites, as well as the maxillae and coxae, are of a 

 pale greyish yellow-brown. The loth, nth, and 12th segments 

 of the abdomen form complete rings not divided into tergites 

 and sternites. These segments, and the upturned flagellum 

 they carry, are darker than the sternites, and paler than the 

 tergites. The 12th, or last segment, bears on each side of 

 the anus the dome-like opercula closing the apertures of the 

 glandulae odoriferae. The soft parts separating the chitinous 

 tergites and sternites, and intervening between them and the 

 cox^ and between the various joints of the legs, are of a dirty 

 whitish brown hue. 



Flagellum. — This is three-jointed, and measures about 

 2 mm. in length by about "5 mm. in breadth. It is cylindrical, 

 or nearly so, in shape. The first joint is rather short and 

 bears no setae. The second joint is very short and bears eight 

 or nine long setae, each rising from a dome-like base. The 

 third joint is longer than the sum of the other two, forming 

 about three-fifths of the organ. It bears numerous long setae. 



Eyes. — Two ocelli are present, placed on the caput above 

 the bases of the palpi. Each is oval, but rather irregularly, 

 being narrower in front than behind. Each is moderately 

 convex when viewed in profile. 



Palpl — Not very slender. About i"49 mm. in length ex- 

 clusive of the maxillae. Each is thus less than half the length 

 of the body. The trochanter vcv^^.smxq.'s, about "3 mm. in length. 

 The anterior border is straight. The inferior border is broadly 



