542 INSECTA MADERENSIA. 



Tachyusa may be known by its narroAv and more or less constricted outline, by 

 its usually finely pubescent sericeous siu-face, its rudimentary paraglosste, and by 

 its somewhat slender and elongated limbs, — the two front tarsi of which, as in 

 Ilonialota, are quadriarticulate ; whilst the hinder pair, as in CaJodera (which 

 howev^er is altogether pentamerous), nearly equal the tibiae in length, and have 

 their basal joint exceedingly long. The sole Madeiran representative is neverthe- 

 less, in external contour, anything but typical, being attenuated behind and 

 sliglitly depressed, and partaking more of Homalota in general appearance than 

 of tlio ordinary Tachyusai : still, its lengthened limbs, and the proportions of its 

 greatly produced posterior feet point to the present genus as the only one capable 

 of receiWng it, — with which indeed in its subaquatic habits it likewise coincides. 

 There is a peculiarity moreover in the fore-tibife of the T. raptor ia which I do not 

 observe in any of the European species, namely that they are obliquely trun- 

 cated towards their inner apex*, and have two minute spines (or setae) at the upper 

 extremity of the notch (as in the Carahidce), — a structure which, in conjimction 

 with the rapid movements of the insect and its prominent eyes, would seem 

 rather to betray a carnivorous, or at any rate a prehensile tendency. The tibial 

 spurs, also, appear to be but imperfectly (if indeed at all) developed.; though, 

 having had but a single specimen for dissection, I may, considering the minuteness 

 of the objects, be mistaken as regards this. 



411. Tachyusa raptoria, Wall. 



T. ni^ra minutissime punctulata pubescens subnitida, protliorace subquadrato postice leviter con- 

 sitricto, elytris apicem versus fuscescentibus, abdoiuine postice attenuate, femoribus tibiisque 

 infuscatis, tarsis pallido-testaccis. 



Lons;. Corp. lin. 1^. 



Habitat Maderam australem, inter lapillos per litora fluviorum, semel tantum reperta. 



T. minute, black, most delicately punctulated and pubescent, sligbtly shining, and depressed. Head 

 rather wider than the prothorax ; and with tlie eyes large and prominent. Prothorax a little 

 elongated, and narrowed behind (the sides being suddenly straightened inwardly about the 

 middle); and with a just perceptibly ffineous tinge. Elytra obscurely fuscescent towards their 

 apex. Abdomen strongly margined, and gradually attenuated behind. Antenna and legs much 

 elongated ; the former with their apical joints a little diluted in colouring ; the latter with their 

 femora and tibije brownish, but with their tarsi (the hinder ones of which are exceedingly long) 

 jiale testaceous. 



Apparently rare, — or perhaps only local, since from its minute size and insig- 

 nificant general appearance it would he very liable to be overlooked. The only 



• Very faint traces of this oblique emargination are to be detected even in Calodera (causing the apex 

 of the tibiae to seem slightly narrowed), but there is no appearance there of the minute spines. 



