r i K ( ' ( > 1 



407 



gC, l)Ut a greater number ot with 



dler number of individual slirul>s. Tin- the overhead 



^paccs and make a den-e >hade. while the louer fore I i- open. Beech 

 and sugar maple are char.u teri-t it . Theft &V ^tages arc li 

 together by transitional stages. 



Ot" the many speeies tabulated hy Shelford, the ti^-r beetle- and 

 grasshoppers may be selected to illustrate succcion in relation to : 

 development. The tiger heetles, Cicindela, breed in the .-ubterranean 

 >tratum and feed in the ground stratum. 



TIGER BEETLES OF FOREST SUCCESSION (SHELFORD) 

 In these tables C signifies common; F, few; P, present 



With the tiger beetles the character of the soil, as regards suitability 

 for oviposition, is the chief factor that determines the presence or 

 absence of this or that species. C. sexguttata, which comes in with the 

 white oak- red oak- hickory forest, lays its eggs under loose leaves or in 

 little irregularities in the ground, which contain a little humus and are 

 slightly shaded; it is rare, however, in very shady situations, such as 

 those of the beech and maple forest. 



Of the orthoptera named in the following table, numbers i to 6 

 breed in the subterranean stratum and feed in the ground stratum; 

 6 feeds also in the vegetation strata; 7 breeds in the ground stratum, 

 feeds in the herbaceous; 8 and 9 breed and feed in the herbaceous; 

 10 and ii breed and feed in the tree stratum; 12 breeds and feeds in 

 the subterranean-ground stratum; and 13 in the ground stratum. 



The table indicates that the successive changes in vegetation are 

 accompanied by corresponding changes in the character of the orthop- 

 teran fauna. Other insects or other animals also illustrate the same 

 phenomenon of ecological succession. During the success \e \egeta- 

 tional stages the numbers of a species increase until optimum conditions 

 of habitat are attained, and thereafter decrease. 



