102 Prof. Asa Gray on t/ic Question 



8. Ltthohius Saussurei, n. sp. 



Lamitia ccphalica obcovdata, fero aMjue loiiga ac lata, latcribu.s 

 semicirciilariter rotundatis, laivis, pilis sparsi.s vcstita. An- 

 tenna' sat longa?, corporis dimliliani longitudineni hand assc- 

 qucntcs, articulis 27 parce sctosis, ultimo penultimnm lon- 



i^itudinc hand nndto siiperante, composita\ Ocull . 



Coxir ])cduni maxillariuin socundi })aris dentibus 5 + 5 

 nic^errimis, brcvibus, validis ainiata', sinu nicdiano subpro- 

 tundo. Scuta dorsuah'a anteriora Icvius, ])0steri()ra maiii- 

 lestius rugulosa, at non granulata,subglabra, 9"", 11"'^, 13""" 

 angulisproductis,7"'"inargine postico mcdioprofundcsinuato. 

 Fori coxales 5, 6, 7, 6 niagni, subrotundi. Pedes primi paris 

 calcaribus 2, 3, 2. Pedum anaJiuni articulus primus calcari 

 singulo, lateral! arniatus. Pedes anales breves, sat inflati, 

 ungulbus binis, calcaribus 1, 3, 3, 1 armati. Unguis geni- 

 talium femineorum obsolete trilobus, lobo mediano laterales 

 baud multo superante ; calcarium duo paria. Color casta- 

 neus vel brunueus. 



Longitudo corporis 23 millim., antennanim 9 millim., pedum 

 analium G-7 millim. 



Hah. in Mexico circa urbem Orizaba [H. de Saussure). Unum 

 tantum specimen ( ? ) vidimus. 



Upsala, February 10, 1875. 



XXV. — Do Varieties wear out, or tend to loear out ? 

 By Professor AsA Gray *. 



Tins question lias been argued from time to time for more 

 than half a century, and is far from being settled yet. Indeed 

 it is not to be settled either way so easily as is sometimes 

 thought. The result of a prolonged and rather lively discus- 

 sion of the topic about forty years ago in England, in which 

 Lindley bore a leading part on the negative side, was, if we 

 rightly remember, that the nays had the best of the argument. 

 The deniers could fairly well explain away the facts adduced by 

 the other side, and evade the force of the reasons then assigned 

 to prove that varieties were bound to die out in the course of 

 time. But if the case were fully reargued now, it is by no 

 means certain that the nays would win it. The most they 

 could expect would be the Scotch verdict, " not proven," — and 

 this not because much, if any, additional evidence of the actual 

 wearing out of any variety has turned up since, but because a 



♦ From Silliman's * American Journal,' February 1875. 



