NO. 1170. THE FA MIL Y G OMI'HODESMID^^COOK. 679 



distinct, prominent callus, the edge blunt, entire; carinae of anterior 

 segments curved sliglitly forward; those of the posterior turned more 

 strongly backward and their posterior corners increasingly produced 

 caudad, usually sharp and dentiform on segments 17 to 19. 



Repugnatorial pores small, dorsal or sublateral, located in a usually 

 distinct cavity near the middle of the marginal calli of segments 5, 7, 

 9 to 19, with the single exception of the genus Marptoclesmus, which 

 lacks pores on segments 11 and 14. 



Below the carinte the segments are smooth or finely rugulose, with a 

 small secondary carina above the insertion of the legs. 



Anterior subsegments smooth or very minutely striolate longitudi- 

 nally under a lens. 



Supplementary margin long, membranous, finely striate longitudi- 

 nally, not pectinate. 



Penultimate segment very short, its small and dentiform carinne 

 included between and seldom exceeding those of segment 18, which are 

 many times larger. 



Last segment very short, triangular, the apex narrow, truncate or 

 somewhat rounded, the entire sclerite bearing 16 seta?, as follows: Two 

 pairs lateral, two pairs marginal, two pairs dorsal, all these rising from 

 small or indistinct tubercles; one pair apical and one snbapical, rising 

 from punctations. 



Anal valves with compressed, elevated margins and two setigerous 

 tubercles, the upper pair placed on the outer slope of the raised margin, 

 the lower somewhiit removed from it. 



Preanal scale subtriangular or rounded, usually apiculate, the two 

 setiferous tubercles more or less developed, located rather close to- 

 gether. 



Sternal si)ace between the bases of the legs broad, except on anterior 

 and posterior segments; the sterna are variously modified by the pres- 

 ence of secondary sexual characters noted below. 



Legs, as compared with other families of the order, rather short and 

 moderately robust. 



Secondary sexual characters. 



This family offers a considerable series of constant secondary sexual 

 characters, several of which are, as far as known, entirely unique. In 

 common with most other Merocheta, the females are somewhat more 

 convex and robust than the males, and have shorter and more slender 

 legs. The more peculiar features are as follows: 



1. The sterna are in most of the larger genera provided in males with 

 two transverse, medianly interrupted sharp ridges connecting the bases 

 of the legs. 



2. Sternum of fifth segment with a pair of small processes located 

 between the bases of the fifth pair of legs: Harniodesmns. 



3. Sternum of sixth segment with two distinctly separated processes 



