Analysis of Heterogeneity in the Population 



307 



places and at the same place in different generations, which would then be inter- 

 preted on the basis of some favored hypothesis, and that would be the end of the 

 study. The condition of the data thus gathered and analyzed left nothing upon 

 which to initiate further investigations into the analysis of the " variation " 

 phenomena that were present. The present method of analysis of the condi- 

 tions in the character examined, and the same would be true of any other, does 

 leave a broad foundation upon which to build further investigations. 



Similar series of observations in other species in the group have been made 

 and brief statements of the findings in some of these are presented, not that they 

 add anything in principle to the conditions seen in L. muUitceniata, but they 

 show that the state found in that species is not limited to it, nor are the prin- 

 ciples which it shows specific in any degree. This species is of the high-plateau 

 group, and for comparison I shall give briefly the conditions in a lowland 

 savannah species L. undecimlineata Stal and L. decemUneata of the temperate 

 portions of the northern United States. Data of the former at two locations 

 Tierra Blanca and San Marcos in the lowland savannahs of Mexico, at Chicago 

 for the latter form in the north. 



IN LEPTINOTARSA UNDECIMLINEATA. 

 The condition presented in the pattern of the pronotum of this species 

 shows many points of likeness to the pattern in the species already examined. 

 The same elements are present in the sys- 

 tem, with some wanting, and a few are 

 added. As in the former species, by 

 proper breeding analyses it can be broken 

 up into a series of groups that are uniform 

 in character, breed true in mass cultures, 

 and in all respects biotypic groups of this 

 character and species. In figure 112 is 

 shown the condition of the pattern as a 

 whole, as far as it is known to exhibit dif- 

 ferences in the pattern within the known 

 range of the species in nature, represent- 

 ing the conditions over the whole known 

 extent of the species. The known range 

 shows that the different conditions can, for 

 convenience, be arranged around the neu- 

 tral or indifferent biotype 7. In L. un- 

 decimlineata the same elements are present 

 as in L. muUitceniata, the combinations in 

 both are the same, and in both similar 

 directions of the modification are found. 

 From biotype 7 in both, 9, 8, 5, and 4 are 

 present in the same condition, displaying 

 the same elements in the identical combi- 

 nations thereof, and vdth the same general range ; biotype 6 is also present, but 

 with an added element, the area forming a connecting element between c and e, 

 and designated in this species as biotype 6a. Biotypes 1, 2, and 3 are uniformly 

 absent in this species, and 4 is not as a rule much developed in any location thus 



Fig. 112. — Diagram representing bio- 

 types and their arrangement in the popu- 

 lation in the species as L. undecimlineata 

 and L. panamensis. 



