38 LAMELLICORNIA. 



Mexican examples (of which I have seen only seven) are dull bluish-black. 

 Burmeister says " viridi-atrum, opacum." All the numerous specimens received from 

 Costa Rica and Chiriqui are of a rich dark blue colour. Well-developed males have a 

 moderately-elevated umbo. The species belongs to a section of the genus (Burmeister's 

 Section III.) in which the " carina humeralis " is absent, and in apparent compensation 

 the short carina on the humeral callus is strongly developed. The true relation of this 

 carina is evident when the interstices are counted, it being situated on the seventh from 

 the suture (the position of the callus), whilst the humeral carina is at the base of the 

 ninth, close to the eighth stria. 



The carina exterior to the humeral one, which is the upper edge of the epipleura, is 

 strongly nexuous in those species which have a humeral carina, but becomes straight 

 in those in which it is absent, viz. in D. mexicanum and allies. 



The male in D. mexicanum is distinguished from the female by very slight characters ; 

 the sutures of the ventral segments are equally developed in both sexes, the segments in 

 the male being only a little more contracted in the middle ; but the hind femora have 

 an obtuse tooth beneath near the apex, which is wanting in the female. 



6. Deltochilum scabriusculum. (Tab. II. fig. 16, ? .) 



D. dentipecU (Eschsch.) proxime affinis ; mnlto minor ; capite et thorace nitidis, crebre sequaliter punctatis ; elytris 

 punctulato-striatis, interstitiis passim subvermiculato-rugosis punctisque intermixtis, lateribus ntrinque 

 bicarinatis. 



5 . Femora antica subtus unidentata ; tibise posticas medio subangulatim incurvatse. 



Long. 23-25 millim. 6 $ . 



Hah. Mexico, Tlacotalpam (Salle), Jalapa, Cuernavaca, Misantla, Tapachula in 

 Chiapas [Edge) ; Guatemala, Coban in Vera Paz (Champion). 



Belongs to Burmeister's Section L, hitherto containing one species only. It differs 

 from D. dentipes, besides its more oblong form and punctured head and thorax, in 

 wanting the strongly-marked male peculiarities in the anterior and posterior tibise and 

 ventral segments exhibited by that species. Burmeister gives as a character of Section I., 

 " Elytris in margine externo bicarinatis," but does not point out the singular homolo- 

 gical relationship of the carinse to those of the rest of the genus. In fact, the usual 

 short humeral carina becomes here the margin of the elytra, and runs from the base 

 nearly to the apex, the true marginal carina, i. e. the upper edge of the epipleura, being 

 removed to the middle of what consequently becomes an epipleura, augmented by the 

 addition of one of the normally dorsal interstices. In correlation with this the 

 remaining dorsal interstices are expanded laterally. The second carina is nothing but 

 the elongation of the outer carina on the apical callus. The humeral callus on the 

 same (seventh) interstice is absent. 



An example from Tlacotalpam is figured. 



