3l8 WILLIAM LAWRENCE TOWER. 



and the summer of 1908 and part of 1909. It was subjected 

 to various analytical experiments, all of which tended to show 

 that the type was a relatively stable one. Individual pairs, when 

 inbred, gave a very definite pure line culture, and groups mated at 

 random gave the same result; but, as in the colony in the Balsas 

 River, there appeared sporadic individuals, widely separated from 

 the parent stock, which, when inbred, behaved very much as 

 mutants are supposed to do. 



L. decemlinenta X L. oblongata X L. muUitceniata. 

 Exp. No. C. H. 156.8 Tucson. 



A culture of the same material was placed at the Desert 

 Botanical Laboratory of the Carnegie Institution in the desert 

 of Southern Arizona at Tucson near the foot of Tumamoc Hill. 

 In this experiment two males and two females of L. decemlineata, 

 from Exp. No. 99, g. XIII, from typical stock at Chicago, two 

 males and two females of L. oblongata from Exp. No. 619, g. XI, 

 and two males and two females of L. multitczniata, from Exp. No. 

 543, G. XI, were mated in the early part of June. This culture 

 was confined in a cage six feet square on the ground and three 

 feet high, covered with wire eighteen meshes to the inch, thus 

 eliminating all selection by insectivorous enemies. Solanum 

 rostratum was supplied as food in sufficient quantity. During June 

 and July these reproduced abundantly and gave a large progeny 

 which emerged late in July and early in August. In this first 

 hybrid generation at Tucson there was, as in the other cultures, 

 a blending of the materials introduced into the experiment, but 

 in this culture L. decemlineata was the dominant member of the 

 cross, although not completely. 



In the larvae six types were observed : 



1. Those which on inspection appeared to be L. decemlineata. 



2. Those which were L. oblongata. 



3. Those which were L. muUitceniata. 



4. Those which were intermediate between L. decemlineata and 

 L. muUitceniata. 



5. Those which were intermediate between L. decemlineata and 

 L. oblongata. 



6. Those intermediate between L. oblongata and L. muUitceniata. 



