INSECTA MADERENSIA. 367 



Male, with the legs broad and robust : the two anterior tibia slender, and with their apical spine 

 obsolete, very obscurely crenulated internally, and entire, being narrow throughout their entire 

 length and scarcely at all emarginated towards their extremity, — with the extremity itself slightly 

 incurved ; the intermediate ones with the spine large and robust, and, likewise, slightly incurved 

 at their extremity ; the hinder ones constricted before their extremity, — the extremity itself with 

 its external surface suddenly and immensely expanded out, the inner angle being obliquely 

 truncated so as to form a heel (which is immensely produced, and somewhat thumb-shaped, being 

 obtuse or rounded at its termination) behind the apex, and the outer one being produced into 

 an excessively prominent and acuminated process. 



Female, rather larger; with the legs slenderer, though not shorter, and simple. 



In point of size, tlie present Atlantis is intermediate between the A. lamelllpes 

 and the A. noctivagans ; nevertheless it has a far greater affinity with the latter 

 than with the former, the comparative shortness of its antennae, the minutise of its 

 colour and sculpture, the robust apical spine of its intermediate legs, and (to a less 

 extent) the construction both of its anterior and posterior ones, being all partially 

 coincident with the corresponding details of that insect. So much indeed is this 

 the case, that before I had carefully examined the few specimens which I possess, 

 I had imagined them to be but largely developed examples of the A. noctivagans. 

 A more critical comparison however has subsequently convinced me that they are 

 certainly distinct, — since, apart from the modifications of their male tibia3, the 

 many small peculiarities which they display make up, in the aggregate, a consider- 

 able amount of difference, and must unquestionably establish them as a separate 

 species. They may be known from the A. noctivagans (with Avhich alone they 

 could be confounded) by their greater bulk and somewhat less deeply sculptvired 

 surface, by the slenderer club of their antennae, and by the tibiae of their males, — 

 of which the anterior pair are narrow, and almost entirely straight along theu' inner 

 edge (being scarcely perceptibly constricted, or emarginated, before then* extre- 

 mity so as to shape-out a rounded calf towards their base) ; whilst the posterior 

 ones present a peculiarity of dilatation which is very remarkable, being immensely 

 produced behind (/. e. at the postapical projection formed by the oblique truncation 

 of the inner angle) into an exceedingly prominent and thumb-shaped heel, which 

 is not only of gigantic dimensions compared with that of the^. noctivagans, but is 

 likewise rounded and obtvise at the extremity, instead of acute. The only male 

 specimen of the A. calcatrix wliich has hitherto come beneath my notice was 

 captured by myself from under a stone at the edges of the Levada of the Ribeiro 

 Erio, dm*ing the spring of 1849 : but I have taken females, which I do not 

 hesitate to refer to the same species, from amongst moss and lichen on the trimks 

 of the old vinhaticos on the eastern limits of the elevated plain of the Fateiras. 



280. Atlantis noctivagans, Woll. 

 A. elongate- subovatus piceo-niger, pube viridescenti-, aurescenti-, et cuprescenti-micante plus minusve 



