TWO NEW EMBIID.E. 25 



thin and flattened in the central part of the faces, but becomes 

 columnar at the corners. Cell-boundaries are not easily seen. 

 The large central space of each chamber is filled with a colloid 

 secretion, more or less shrunken in alcoholic material. This 

 substance, the silk, is carried to the tips of the hairs through 

 ducts of varying length, one from each chamber (Fig. 4, b}. 

 The terminal hairs (Fig. 4, a] are arranged in a row around the 

 edge of the plantar surface of both the metatarsus and the second 

 tarsal joint. Though the latter is devoid of any secreting gland 

 it possesses several ducts leading through it from the metatarsus. 

 Some of the ducts lead along the periphery of the joint, others 



FIG. 4. Rmbia texana. Portion of metatarsus, showing glands ; a, spinning 

 bristle ; l>, duct of silk-tube ; r, ampulla at base of duct. 



pass between the gland-chambers. The foot-tendon lies in large 

 part between the two lower series of glands. 



In the glands, each duct arises from a remarkable ampulla (Fig. 

 4, c, d, e}. The wall of the duct suddenly becomes thickened, 

 and then subdivides into four or five rays, which are continued in 

 the form of the equidistant meridians of a sphere and meet again 

 in an end-plate opposite the point of subdivision. Thus the 

 lumen of each duct terminates proximally in four, or rarely five, 

 large, elliptical or ovoid, lateral openings. At the base of each 

 opening is a radial arrangement of fine processes, possibly the 

 expression of the silk being drawn into the lumen of the tube. 



UNIVERSITY OF TEXAS, AUSTIN, TEXAS, March 22, 1901. 



