1 88 Heredity and Eugenics 



United States and southern Canada; L. multitaeniata 

 entirely to the southern portion of the plateau of Mexico, 

 and L. oblongata to the Balsas Valley and the Oaxaca- 

 Guerrero Highlands. These species intercross freely under 

 experimental conditions and represent the following con- 

 trasting characters for consideration. The general ground 

 color of the larvae of L. decemlineata is wine red, that of 

 L. oblongata and L. multitaeniata chrome yellow. L. decem- 

 lineata and L. multitaeniata have two rows of spots 

 along the side in the larvae, while L. oblongata has one. 

 L. oblongata, as shown in Fig. 60, is long and oval in outline ; 

 L. decemlineata, as shown in Fig. 69, is more rounded; 

 and L. multitaeniata is robust in type. There are also color 

 differences between the species, which need not concern us 

 here. Three experiments will serve to illustrate the pur- 

 pose of this paper. 



In 1905, twenty L. decemlineata, from a pedigreed cul- 

 ture, from Chicago, twenty L. oblongata, from a pedigreed 

 culture at Cuernavaca, and twenty L. multitaeniata, derived 

 from an isolated standard locality in the valley of Mexico 

 south of Guadalupe, were placed on an isolated island in the 

 Balsas River. This island was fairly well covered with a 

 growth of Solanum rostratum, or a closely related form, upon 

 which all three species would feed. As far as could be 

 discovered, the island was devoid of any individuals of L. 

 oblongata, which occur very sparingly in that general region, 

 and the neighboring banks of the river and the islands were 

 all searched, but they afforded no trace of L. oblongata. 

 These introduced beetles were allowed to breed and gave 

 the first hybrid generation in August, 1905. In this 

 generation only the adults were seen and of the adults we 

 could recognize definitely five forms : (A) Those which on 



