NO. 1170. THE FAMILY GOMPIIODESMIDJE—COOE. 693 



Viewed from the ine.sial face, tlie broad base of the flagellum is seen 

 to be mer-ely a (concave exi)aiisi()ii, siigyestiiij;- that of Neodesium, not- 

 withstanding the great difference in the form of the copulatory lej?s 

 and the process of the sixth segment. The only other genus with which 

 MychodcKinus will bear comparison is Sphcnodesmus. 



MYCHODESMUS MACRAMMA, new species. 

 (]'l:itc LVI, fifrs. 2a,2b.) 



Vertex smooth and even, without hairs; suture and sulcus distinct. 



Olypeus without hairs, ratlier Hat; three i)airs of setiferous jmncta- 

 tions, the ui>i)er pair farther apart than in Neodesmun. 



Antenna; rather robust, with the sixth joint slightly thicker than the 

 others; moderately hirsute, with short liairs. 



First segment subreniform, not symmetrical, the anterior margin 

 being carried around to meet the i)Osterior, which is nearly transverse, 

 but has the usual broad emargination in the middle. 



Segments dor.sally smooth or faintly coriaceous in the middle, becom- 

 ing riignlose laterad, distinctly so upon the carimc. 



Lateral carin* with distinct raised margins in front and behind ; mar- 

 ginal calli moderately distin(5t and prominent, distinctly broader on 

 poriferous segment, the cariuic of which are also more distinctly 

 rounded ; posterior corners s(]uared on anterior and middle segments, 

 produ<!ed only on the posterior, and there only broadly. 



Kepngnatorial pores located in rather small but distinct cavities, 

 those of the anterior and middle segments facing more nearly hiterad 

 than those of the i)()sterior, but the cavities are not placed so far laterad 

 as to cause the edges to ajjpear emarginate, as in some species. 



Penultimate segment of moderate length, the carina' broader than 

 long, rounded, not exceeding those of the eighteenth segment. 



Last segment of moderate width, triangular, abruptly narrowed below 

 the narrow, distinctly truncate apex. 



Anal valves with margins rather distiiujt and narrow, though not 

 strongly compressed nor prominent; surface of valves and preanal scale 

 faintly rugulose. 



Sterna nearly naked, a few long hairs near the posterior margin. 



Sternum of segment 6 with lateral edges somewhat sloping; the two 

 lobes are broadly rounded and more prominent laterad, sloi)ing gradu- 

 ally mesad into the broatl and shallow notch, the corner of which is 

 greater than a right angle; the process is moderately hirsute, with long 

 hairs, as are the prominent coxa' of the sixth pair of legs. 



Legs moderately hirsute, with rather short hairs, a few long hairs on 

 the basal Joints more numerous cephalad; the second joint is only 

 slightly inllated on the dorsal face. 



Copulatory legs (Plate LVI, ligs. 2a, 2&). 



Color of alcoholic specimen distinctly brown, darkest on the dorsal 



