220 INSECTA MADERENSIA. 



the outer one, did not the transparency of the latter allow the former to be seen 

 through it frotn its commencement, — thus disclosing the fact that it is really an 

 additional plate (arising from then- common hase), and not merely an apical piece 

 joined to the anterior edge of the true mentum, as prhnd facie it might seem to 

 he. This rectangular internal lamina hears some resemhlance to a corneous 

 lio-ula, — which indeed I should at first have heen inclined to have considered it, 

 had I not succeeded in dissevering the undouhted ligula from it (with the palpi 

 affixed), which is so exceedingly delicate as to he scarcely appreciahle whilst 

 attached to the dark solid sm-face over which it is spread. 



There are hut few known species of Thorictus ; and as respects their hahits very 

 little indeed has heen hitherto ascertained. I have no hesitation however in 

 regarding them as inhahitants of Ants'-nests, — the few stray specimens which I 

 have ever captured having been found beneath stones in positions very similar to 

 those in which Cossyphodes occurs, and theu- very curious, subcorneal feet being 

 precisely in accordance with what we are accustomed to perceive amongst insects 

 of an Ant-associating tendency. 



172. Thorictus Westwoodii, JVuU. (Tat). IY. fig. 6.) 

 T. obtusus mbescenti-badius iiitidissimus, punctis dispcrsis miuutissimis vLx (prsesertim iu elytris) 

 perspicuis obsitus, prothorace maximo convexo ad latera valde rotundato-ampliato (in medio 

 latissimo necnon ad basin ipsam fortiter constricto), elytris pone discum convexis, singulo costa 

 basali abbreviata (mox intra humerum sitfi) iustructo, antenuis pedibusque obseurioribus. 

 Long. Corp. lin. 1. 



Habitat circa urbem Maderse Funchalcnsem, rarissime: duo specimina tantuiu vidi, unum sc. ad 

 Praya Formoza Maio ineunte a.d. 1848 et alterum in coUe aprico prope Ribeiro de Sao Gongalo 

 mense Januario a.d. 1819, sub lai)idibus a mcipso invcnta. Genus, ut structura tarsorum sub- 

 conica atque habitus generalis valde anomalus indicare videntur, formicaruui nidos nisi fallor 

 colens. 



In honorcm luminis Entomologicoruiii J. 0. Westwood, arm", qui jam per plures annos indagationi 

 deditus Entomologise scientiam insulis Britannicis laudibus amplificavit, banc spccieni Thoricti 

 ccrte novam institui. 



T. (ibtuse (especially in front), bright reddish-chestnut, exceedingly highly polished, and nearly 

 glabrous (there being just perceptible indications, beneath the microscope, of a few short and 

 scattered hairs towards the sides, — though especially about the humeral angles of the elytra). 

 Prothorax very large, and widest about the middle (where it exceeds the eh'tra in breadth), with 

 the sides uniformly rounded, though much constricted at the extreme hinder margin ; beset with 

 minute and distinct punctures; extremely convex, particularly in front ; and sometimes with an 

 obscure oblique impression (as in the plate) on either side behind, — which at others however 

 would appear to be obsolete. Elytra very convex (and semitransparent) behind the middle of 

 the disk, being comparatively depressed towards the anterior margin ; beset with most minute 

 and distant punctures (even less perceptible than those on the prothorax, and only to be 

 distinguished uuder the microscope) ; and with an exceedingly abbreviated costa, or ridge (and a 



