14(j GEO. H. HORN, M. D. 



moderately prominent, narrowly separated from the mouth beneath. Labrum 

 transverse, feebly emarginate, margin sexsetose. Mandibles arcuate acute at tip, 

 not prominent. Maxillse slender, ciliate and spinous within, the outer lobe slender 

 and with two equal joints, the palpi slender, the terminal joint elongate-oval and 

 acute. , Mentum deeply emarginate, toothed, (except in Pionycha), ligula moder- 

 ately prominent, the tip bilobed or narrowed and bisetose, paraglossse slender 

 and acute usually longer than the ligula, palpi slender, last joint oval acute, the' 

 penultimate bisetose in front. Thorax elongate, narrower thfVn the head, margin 

 feeble, sides with a setigerous puncture near the middle and at the hind angle. 

 Body subpedunculate, scutellum not prolonged between the elytra. Elytra oblong- 

 oval, not margined at base, lateral margin distinct and entire, without internal 

 plica, apices rounded without sinuation, disc striate, third interval with three 

 indistinct dorsal punctures. Prosternum slightly prolonged at tip. Mesosternum 

 oblique, the epimera very narrow. Metasternal epimera distinct, posterior coxae 

 contiguous. Legs slender, middle and posterior tibife slightly ciliate externally, 

 the anterior emarginate, its spurs very small. Tarsi slender, the first joint as long 

 as the next two which are oval, the fourth broad, deeply bilobed and j^apillose 

 beneath, claws pimple dentate or pectinate. 



The tarsi are alike in the sexes. The males have one seta on each side of the 

 apex of the last ventral segment, the females two. 



The tribe as here constituted contains not only the Ctenodactylides of 

 Lacordaire but also his Trigonodactylides. 



Two groups may be indicated. 

 Thorax narrow, elongate. Ligula slender usually narrowed in front. 



CTENODACTyL.JE. 



Thorax nearly or fully as wide as long. Ligula bilobed at tip HexagonijE. 



The Ctenodactyl/E alone are represented in our fauna by Lepto- 

 trachehhs which occurs in the Atlantic region. 



Regarding the Hexagon:^ as typified by Hexagonia (= Trigono- 

 dactyla) the only genus known, it can only be said that it is remarkable 

 that such an extraordinary error should have been allowed to pass current 

 from one author to another as has been done in the description of the 

 maxilla. After having carefully dissected the mouth of Trigonodactyta 

 the parts were placed under the microscope and an appearance of the 

 tip of the maxilla seemed to indicate that it was really terminated by 

 a moveable hook. 3Iy custom however has been in doubtful cases to 

 surround the parts with a drop of water on glass when all sutures and 

 other lines become apparent. Without wishing to describe in detail the 

 structure of the maxilla the reader is referred to the figure. 



It will be observed in the two groups above indicated that the paraglossae 

 arise apparently by their base from the side of the ligula in the Cteno- 

 dactyli, but are prolonged to the base of the ligula in the Trigonodactyli. 

 The difference is however more apparent than real. If the ligula bo 

 observed from the inner side the paraglossae will be found adherent to 

 that side, their outer edge being very close to that of the ligula itself. 



