417] COLORS OF TIGER BEETLES— SHELFORD 23 



understood b.y a eomparisou with the larval segments (Fig. 99 a, h, and 

 aa). If a and b joined to give the first marking that appears, «a stand- 

 ing out clearly and all of the rest joined laterally, one would have the 

 condition found in the development of the adult color. 



No change takes place in the thorax except the development of a 

 center of. tbo on the middle line of the meta-sterniim which probably 

 repi-esents the attachment of the large hind wing muscles (Fig. 102), 

 until the coloration of the abdomen is has been completed in the veuti'al 

 side of the third, fourth, and fifth, and last abdominal segments; this j 



having proceeded from behind forward. At the end, 12 to 15 hours 0' i 

 (Fig. 103), it will be noted that the hind coxae, the ante-eoxal pieces, ] 



the epistema of the metathorax and the coxae of the other segments 

 have received a quantity of pigment and a new; center has developed 

 behind each metathoracic leg on the metathoracic sternum. The next 

 stage represented (24 to 36 hours, Fig. 104) shows a general diffuse 

 pigment on the entire ventral surface except the outer sides of the 

 metathoracic coxae which long remain unpigmented. The ante-coxal 

 piece is nearest complete. The great possibilities of being deceived as 

 to position of the color centers is shown by the fact that the abdominal 

 centers and center behind the legs on the metathoracic segments is lost 

 entirely in the last stage of the development. 



Conditions on the dorsal side are very simple and centers appear 

 just as in the larvae (Fig. 100) two in number on each segment, begin 

 on the last segment, and move forward fusing in the middle line, and in 

 course of about 10 hours after emergence (Figs. 106 and 107) the color 

 of the dorsal side of the abdomen is practically complete. 



In regard to the color centers of the ventral side of the abdomen 

 it may be said that they are the same in number and arrangement as 

 found by Tower on the ventral side of the abdomen of the potato beetle 

 larvae. The abdominal centers are serially homologous. The pattern , 



of the dorsal side of the abdomen of the larvae if Leptinotarsa is similar ^/ 

 to that of the ontogenetic ventral of the adult C'icindela. The upper side 

 of the abdomen in the potato beetle larvae is divided with respect to 

 these structures because growth, bulging, and wrinlding due to the 

 extension divide the dorsal side into two parts, and have resulted in the 

 separation of the centers into two rows or bands (see Tower. 1906: 

 PI. 18). In the larval Cicindelidae, however, it is the ventral side that 

 is extended in the process of the development and which may be wrinkled 

 and the centers are separated just as in the case of the dorsal side of the 

 abdomen in the larvae of Leptinotarsa. There is never any tendency for 

 the dorsal side of the cicindelid abdomen to wrinkle ; in fact it is reduced 

 as compared with ventral. On the ventral side of the adidt Leptinotarsa 

 abdomen six centers appear but these are not divided as to the middle 



