502 INSECTA MADERENSIA. 



Genus 171. HADRUS. (Tad. XI. fig 4, 5 et C.) 

 Dejean, Cat. (3'^"' edit.) 214 (1837). 



Corpus mediocre, plus minusve ovale : fronte (XI. 5 a, 6 a) ad latera Icviter elevata, ad apicem piofunde 

 biloba : prothorace ad latera complanato : metastemo (XI. 5 h) postice vix bifido : ehjtris sub- 

 c-onnatis : alis obsoletis. Instrumenta cibaria (XI. 5 a, 5 c, 5 <f, 5 e, 6 a, 6 6, 6 c) fere ut in 

 Opatro, sed mentum (XI. 5 e, 6 c) quasi e laminis duabus (una ad alteram arete applicata) forma- 

 tum, supcra subrotundata basi truncate., infera ad angulos anticos porrecta acuta (superne con- 

 spicu&) ante angulos sinuate. Pedes graciles : tibtis niinutissime setulosis, ad apicem externum 

 (prajsertim in anticis) oblique excavatis ; anticis vLx dilatatis : tarsis heteromeris ; posteriuribm 

 (sed prsesertim posticis) articulo primo longiusculo ; ultimo in omnibus elougato, unguiculis sim- 

 plicibus munito. 



Ab a^poii robustus. 



There is no Heteromerous gcuus so universally distributed throughout the 

 ]\[;xdeiran group, or at the same time so truly indigenous, as Rach'us, — there being 

 scarcely a siagle rock, large or small, on which one or the other of the three repre- 

 sentatives described below does not abound. The oral organs of the whole of this 

 section of the Colcoptera are so exceedingly similar, that we can scarcely expect to 

 find any great distiactive featiu'es there ; nevertheless the mentum of Hadriis is 

 very remarkable, — the projecting angles (so apparent from above, and which 

 perhaps should be more strictly regarded as lateral prominences of the basalhj 

 corneous ligula) of its vmder portion gi^dng it a peculiar character, which does not 

 exist, so far as I am aware, in the allied forms. The species have all the habits of 

 the typical Melasomes, — secreting themselves beneath stones in exposed places on 

 the coast, or between the rough basaltic blocks of higher altitudes. They are 

 usually to be found in company with the Ilelopidce, Scarltes ahbreciatus, and the 

 Laparocerus morio ; and are of an eminently gregarious natiire. 



382. Hadras alpinus, Woll. (Tab. XI. fig. 5.) 



H. oblongus niger subtilissime et creberrime granulatus, elytris vix substriatis. 

 Long. Corp. lin. 0-7. 



Habitat sub lapidibus, foliisque arborum dejectis, per partem Maderse sylvaticam, toto anno frequens. 



H. oljlong (being larger and more parallel than the other species), black, almost free from scales, and 

 most delicately and closely granulated all over. Elytra with the faintest possible indication of 

 stria;. Antenna and tarsi slightly piceous, or fuscescent. 



Known at once from the followiag two species by its larger size, more parallel 

 outline, and by its most closely and delicately granvQated and less scaly surface. 

 In its habits moreover it recedes from them altogether, being strictly a mountain 

 insect, — whereas they are confined to comparatively low elevations and sub- 

 maritime spots. The II. alpuiKs is, also, more especially peculiar to the sylvan 



