ONTOGENY 01^ LARVAI, COI.OR PATTERNS. 



H5 



pieces or pleurae, on all abdominal segments and on the prothoracic segments, 

 are found the spiracular spots which are represented on the wing-bearing 

 segments by the wing spots. Beneath these, on the abdominal segments, at 

 the base of the pleurae, are one or, rarely, two basal tergal spots (text-figs. 

 7 and 8). 



On the sternse also a series of color centers is found corresponding to 

 Ihose of the tergae in that there are outer, middle, and inner areas, but these 

 are rarely present as anterior and posterior systems, although frequently in 

 variations there are found strong indications of this anterior and posterior 

 division. These areas continue forward in a homodynamic series over the 

 thoracic segments. 



This system of color centers is not confined to the Coleoptera nor to a few 

 families thereof, but is, I find, of most general occurrence among the Tra- 

 cheates,and,as I shall show in another paper, is the fundamental pattern upon 

 which all insect coloration is founded. With this system of color centers it 



ventral-nerve chain | | 

 inner sternal! 



--,— -.- inner tergal 



- --middle tergal 



--—fat body 

 -- "ouier tergal 



. _,spiracula 



. «baso-pIeural 



•* ^alimentary canal 



I I outer sternal 



I middle sternal 



Tkxt-figure 9. — Diagrammatic representation of a segment, showing the position of the 

 different spots upon the sclerites which compose it. 



is a simple process to develop longitudinal stripes or transverse bars, or both, 

 or combinations thereof. It would also be easy for the followers of Eimer to 

 see in this a system of longitudinal stripes, and for others to see a system of 

 transverse bars, as the fundamental color pattern. In truth, however, this 

 system of color centers is neither of the latter ; it is a metameric repetition of 

 homodynamous areas, or modifications thereof, on every individual segment; 

 and any other interpretation is warped in favor of some particular theory. 

 It is true that the various elements may be so modified as to give on super- 

 ficial examination the general idea of stripes or bands, and as such these com- 

 binations do function in color patterns; but in ontogeny and phylogeny, in 

 experiment and in heredity, each metameric portion of any such color mark- 

 ing behaves as a metameric structure, and in no other way. 



In the larvae of L. undecimlineata at this time the color scheme is to a large 

 extent the same as that shown in text-figures 7 and 8, excepting that the ante- 

 rior and posterior pronotal stripes and all the areas of the epicranium are com- 

 bined into one uniform black color. Upon the abdominal and last two thoracic 



