226 The University Science Bulletin. 



Idiocerus verticis (Say). 



(PI. XXV, fig. V.) 



Length, 1.55 mm.; greatest width, 0.15 mm. Apical portion only sHghtly 

 wider than basal; slightly curv^ed, tip greatly narrowed with extreme apex 

 rounded, chitinization light; strengthening rod extends caudad as far as 

 fourteenth dorsal tooth. Toothed area on dorsal edge occupies a little more 

 than the apical third ; teeth twenty in number, large, rounded, regular, evenly 

 spaced except basally; bear no distinct secondary teeth, though the margin 

 is irregularly roughened suggesting secondary' teeth; the tip bears ten small 

 caudad-pointing teeth along its ventral edge; the ducts are inconspicuous, 

 their circular openings alone being visible; of these apparently two open 

 ventrally, three apicalty, and many dorsally; there is no distinct chitinized 

 connection between the two valves of the pair. 



Idiocerus scurra (Germar) . 



(PI. XXV, fig. 8.) 



Length, 222 mm.; greatest width, 0.28 mm. About the same width for 

 entire length; slightly cui-ved, tip nan-owed but broadly rounded at the ex- 

 treme apex, rather heavily chitinized; strengthening rod extends caudad as 

 far as the twenty-fifth, dorsal tooth. Toothed area on dorsal edge occupies 

 a little more than the apical half; teeth thirty in number, moderately large, 

 rounded, regular, evenly spaced, about the same distance apart for entire, 

 length; bear no secondary teeth; the ventral edge of the tip bears ten small 

 teeth; area of ducts conspicuous, granular in appearance, circular openings 

 visible; two open ventrally, two apically, and many dorsally; the two valves 

 of the pair are joined one to the other by a distinct, elongate, chitinized con- 

 nection present on the dorsal edge of the basal area. 



Idiocerus ramentosus (Uhler) . 



(PI. XXV, fig. 4.) 



Length, 1.96 mm.; greatest width, 0.17 mm. About the same width for en- 

 tire length; only slightly curved, tip greatly narrowed with extreme apex 

 rounded, moderately heavy chitinization; strengthening rod extends caudad 

 as far as eleventh dorsal tooth. Toothed area on dorsal edge occupies a little 

 more than the apical third ; teeth eighteen in number, large, rounded, generally 

 regular with a few double teeth, evenly spaced but farther apart basally; bear 

 no secondary teeth; the tip bears three to four small, inconspicuous teeth 

 along its ventral edge; area of ducts conspicuous, granular in appearance, 

 circular duct openings visible; two to three open ventrally, three apically, 

 and many doreally;, the two halves of the pair joined one to the other by 

 an elongate, narrow, chitinized connection present on the dorsal edge of the 

 basal area. 



Idiocerus snowi Gillette and Baker. 



(PI. XXV, fig. 3.) 



Length, 2.33 mm.; greatest width, 0.22 mm. About the same width for 

 entire length; slightly curved, tip very bluntly rounded, rather heavily chitin- 

 ized; strengthening rod extends caudad as far as eighth dorsal tooth. 

 Toothed area on dorsal edge occupies the apical fourth; teeth ten in number, 



