66 ILLINOIS BIOLOGICAL MONOGRAPHS [-WO 



SUMMARY OP CONCLUSIONS 



1. The color patterns of the tiger beetles are related to elytral 

 structures but not casually; longitudinal stripes in which pigment usu- 

 ally occurs lie in the area of the chief tracheal trunks ; there are seven 

 cross bands in which pigment does not develop, the second and third 

 and fifth and sixth of these are often joined to make one of each pair. 



2. Pigment usually occurs about the bases of hairs which usually 

 lie in the lines of the tracheae. 



3. In ontogeny the elytra show a spotted condition corresponding 

 to the system of cross bauds and longitudinal stripes. The longitudinal 

 stripes are usually more pronounced. 



4. The characteristic markings of the group are composed of spots 

 or elements joined in the longitudinal light stripe areas and areas of 

 cross bands with the loss of various spots or elements which occur in 

 ontogeny; joinings are sometimes oblique and when so markings are 

 sometimes parallel with curved end of the elytron. 



5. Certain particular types of markings made up of a few elements 

 joined in a particular way characterize the majority of species of the 

 group. 



6. These markings as derived from the cross and longitudinal 

 bands are angular; reduction of angles, straightening and turning into 

 oblique positions parallel with the end of the elytron characterize modi- 

 fications of markings. The response to stimuli (high temperature) is in 

 the same direction. 



7. Response to other stimuli appeal's to be in tlie direction of 

 concentric extension of the markings. 



8. The color patterns and structure to which they are related 

 constitute a mechanism, the directions of movement of which are lim- 

 ited, i.e., easier in some directions than others; the color pattern plans 

 bi-eak when the related structures do; hereditary changes and fluctua- 

 tions due to stimvilation during ontogeny are in the same direction; 

 laws governing the mechanism are the same throughout. 



9. These laws when applied to hereditary changes are apparently 

 what is sometimes termed orthogensis. 



10. It is not correct to assume that all manifestations of the 

 ■wing mechanism which appear during ontogeny follow the biogenetic 

 law. 



