70 INSECTA MADERENSIA. 



than 5600 feet above the sea, and far removed from the highest forest limi ts in 

 that portion of the island. The spot moreover being one which, from its exposed 

 nature, could never have been wooded at any time, there is the less reason for 

 suspecting that the T. alticola may be merely a state of the T. citstos, gradually 

 assvuncd since the disappearance of the native timber from the region which it 

 inhabits. '\Mien such causes as these can be shown to have operated, I would at 

 all times make abundant allowances for them, since their effect in certain instances 

 has been already proved to a demonstration : but where there is equally decisive 

 evidence that they could never have been brought into play, small differences must 

 frequently be regarded as of primary importance Avhere, under other cii'ciun- 

 stances, even greater ones might be comj^aratively worthless. For these reasons I 

 am induced to believe that the two insects under consideration may be in reality 

 distinct ; and, until intermediate links, both in aspect and habits, shall have been 

 foiuid to connect them, I think we have sufficient grounds for retaining them as 

 such. The T. alticola tlifi'ers from every form of the T. ciistos which has come 

 beneath my notice in being more brightly polished and of a uniformly darker hue, 

 in haA-ing its prothorax slightly less attenuated behind, its elytra more obscm-ely 

 striated, and its tibia) in all instances much more CAddently infuscate, — more so in 

 fact than is the case with any of the other species. I captm'ed it, on several 

 occasions, dm-iug the ■winter and early spring of 1819, in company with Amara 

 superans, on the bleak exposed ridge, overlooking the head of the Metade valley, 

 between, as abeady stated, the Ice House Peak and the Pico dos Arieros. 



54. Trechus cautus, WoU. 

 T. ovatus antice subattenuatus, convexus piceus, prothorace convexo subquadrato basi vix angustato et 



haud iinprcsso angulis posticis obtusis, elytiis striatis, striis ad latera evanesccntibus, antenuis 



pedibusque rufo-ferrugineis. 

 Long. Corp. liu. 2. 



Habitat in montibus Portus Sancti, sub lapidibus in declivibus graminosis, tempore biberno et ver- 



nali, rarior. 



T. ovate, rather attenuated anteriorly and expanded behind, convex, shining, and piccous. Prothorax 

 convex, subquadrate, the posterior angles obtuse ; with a veiy obscure dorsal channel ; and with 

 no appearance whatsoever of fovea; at the base. Elytra ovate, distinctly striated towards the 

 suture but almost unstriated towards the margin ; with two impressed points on the disk of each 

 near the third stria from the suture, which is obscurely paler than the rest of the surface, espe- 

 cially behind. Antenna, palpi and legs rufo-ferruginous. 



An exceedingly Avell-marked species, and rt'adily known from tlie rest of the 

 genus here described l)y its ovate and somewhat anteriorly-acuminated form, by its 

 convex prothorax, aaIucIi has no appearance whatsoever of foveas or impressions 

 behind, and by the stria? of its elji;ra, although distinct near the sutm-c, being 



