TENEBRIONID/E 81 



As a section of the tribe Asidini the Eurafrican species differ from 

 the American (i) in the marked differences between the sexes, 

 which, in depressa, become extreme, there being few Coleoptera 

 in which the sexes become so completely incongruous, (2) in the 

 more narrowly separated coxae, (3) in the prominence of the inter- 

 coxal process of the prosternum, which, though occasionally dis- 

 appearing as in reichei, is nevertheless generally at least traceable, 

 and as characteristic of the old world species as the deflexion of 

 the process is of the American, (4) in the more slender antennae 

 with the tenth joint more abruptly enlarged, a character which 

 is however subject to some exceptions in both regions, (5) in the 

 almost universally less developed gular pedestal of the mentum, 

 and (6) in peculiarities of sculpture as developed in the more 

 typical species, the tufted tubercles being unknown among the 

 American representatives, although suggested perhaps in the very 

 aberrant Mexican fasciculata Champ. The tendency to become 

 coated with indurated and closely adherent mud is also much 

 more characteristic of the European than of the American species, 

 there being however some exceptions among our genera and many 

 notable exceptions in the Mediterranean fauna, such as depressa, 

 dissimilis, goudoti, politicollis, sicula and other related forms, 

 among which there are assuredly several genera distinct from 



Asida. 



Astrotus Lee. 



The few known species of this genus have the surface throughout 

 coated densely with indurated earthy matter, which becomes vir- 

 tually an almost integral part of the integuments and is very difficult 

 to remove; through this coating the minute setae protrude. The 

 fact that these hairs are not involved in the coating, but are main- 

 tained clean and free from such extraneous substance, proves them 

 to possess a tactile function of direct utility as a means of recog- 

 nizing external impact; they are therefore subject to the laws of 

 natural selection and the diverse forms that they assume in the 

 various genera are of greater value in a taxonomic sense than is 

 usually admitted. This is a general law affecting setae growing 

 from punctures throughout the Coleoptera, but does not concern 

 so evidently the fine dense pile sometimes present, as on the under 

 surface of the Melolonthinse for example. 



T. L. Casey, Mem, Col. Ill, Feb. 1912. 



