1899] THE CHINCH BUG 95 



the Chinch Bug; being- one of the six most destructive insects in 

 the States — this work contains much to interest the general student 

 of insect life. The severity of the attacks by the bugs on corn 

 and grasses is largely clue to their gregarious habits. They have 

 but few natural enemies, but high mortality is at times caused 

 among them by certain fungi, notably Sporotrichium globuliferum. 

 Eeference to the attempted utilisation of this fungus-disease for 

 their destruction has already been made in Natural Science (vol. ix. 

 pp. 6-7). Mr. Webster believes that artificial inoculation could 

 only be worked successfully if the bugs were excessively numerous 

 in wet weather or in damp situations. 



With regard to the origin and diffusion of the species, Mr. 

 Webster brings forward evidence to show that there have been 

 three principal northward lines of migration from tropical America : 

 a western, along the Pacific coast to California ; a central, from 

 the Gulf coast of Texas northward to Winnipeg ; and an eastern, 

 along; the Atlantic seaboard to Nova Scotia. All the adults of 

 the central migration have fully developed wings, but among the 

 eastern race forms with vestigial wings are common. These latter 

 have spread eastward and north-eastward, and in their progress 

 through the New England States have acquired a habit of ravaging 

 grass meadows, which is rarely practised by the bugs of the central 

 migration. 



Several species of Blissus inhabit Europe and Africa, but we 

 can hardly accept Mr. Webster's suggestion that the ancestors of 

 the American Chinch Bug were carried across the ocean by. the 

 equatorial currents. 



Formation of a Human Race. 



In his treatise on in -breeding and crossing in man (" Inzucht 

 and Vermischung beim Menschen," Leipzig, 1897), Dr. Albert 

 Reibmayr brings much erudition to bear upon an old problem, the 

 respective roles of in -breeding and crossing. Close in -breeding 

 is necessary to fix and ennoble a race, but when it is prolonged, or 

 if the material be poor, there is continual risk of weakness, infertility, 

 and degeneration. But it is through in-breeding that a national 

 character is evolved, and the problem of national eugenics is to 

 watch for the crisis when crossing becomes necessary to obviate 

 degeneracy. Thus in history there have been and must be alternating 

 periods of dominant in-breeding and dominant cross-breeding. In 

 America, the author indicates, a new race is being formed by complex 

 cross-breeding, a new race which will lead mankind to new ideals in 

 spite of the reactionary doctrine " America for the Americans." And 

 behind this prophecy — which is always rather gratuitous — there is no 

 .small amount of solid anthropological measurement and statistic. 



