148 COLORATION IN LEPTINOTARSA. 



is also bright opaque yellow, quite different from the translucent pale yellow 

 of the previously described species. Upon the pronotum a change is also 

 found in the reduction of the anterior pronotal band. In the last stage, which 

 is shown in fig. 12 on plate 17, almost no further change of coloration is 

 found. 



Closely allied to multitceniata are oblongata, decemlineata, nihicunda, and 

 juncta. L. oblongata, which in the adult condition is almost undistinguish- 

 able from multitcBniata, is in the larval stages quite different, as may be seen 

 from the representation of the first larval stage in fig. 13 on plate 17. In 

 this form the only color centers that are represented are the spiracular, wing, 

 and baso-pleural thoracic spots. All other spots, as well as all spines, are 

 wanting in the earlier stages of this species. Like multitceniata, it is at first 

 almost white, but soon changes to corn yellow. In the second and third 

 stages no modifications of color occur, excepting the loss of the anterior 

 pronotal stripe in the last stage, although the general body color gradually 

 becomes more opaque and yellow (pi. 17, figs. 14 and 15). This species, 

 oblongata, is quite remarkable for its early complete loss of all but a few color 

 centers ; but that the animal is not without the fundamentals of these is shown 

 by their brief appearance in the late embryo, and by their reappearance as 

 color centers in the pupa and imago. 



L. intermedia, rubicunda, and decemlineata present stages of development 

 almost exactly like those of multitceniata. All have in the first larval stage a 

 complete system of color centers and a full armament of spines, as are shown 

 in rubicunda in fig. 16, and in decemlineata in fig. 19 on plate 17. The gen- 

 eral body color of these forms differs from, that of multitceniata in that rubi- 

 cunda is bright red, intermedia a dull yellow, and decemlineata a dull red. In 

 the second stage each of these four retains the spiracula, wing, and all baso- 

 pleural spots, and the inner and middle tergal pairs of color centers on the last 

 two thoracic and the first three or four abdominal segments. The outer part 

 of the anterior band on the pronotum is lost in rubicunda in the last instar, 

 and in intermedia and decemlineata in the second instar. 



The species juncta and dejecta also exhibit interesting stages of color 

 ontogeny. In juncta, in the first larval stage, only the spiracular and 

 baso-pleural spots are present, and there are no spines (pi. 17, fig. 22). 

 In the second and last stages (figs. 23 and 24) the baso-pleural spots have 

 been obliterated, so that only the posterior pronotal band remains, while the 

 baso-pleural spots of the thoracic segments are small or wanting. Often all 

 the color areas are light brown in color. 



These species of Leptinotarsa all belong to the lineata group, which con- 

 tains the most generalized members of the genus. In the coloration of the 

 larvse of these beetles I find that in undecimlineata, signaticollis, angustovit- 

 tata, diver sa, multitceniata, intermedia, decemlineata, rubicunda, and melanO' 



