28 ILLINOIS BIOLOGICAL MONOGRAPHS [422 



e. g., Lacchophilus maculosus (Fig. 39, PL IV), a concentration of the 

 pigment around the markings. Even where the markings are absent 

 or almost so the denser pigmentation is present. This seems to have 

 obliterated ontogenetic markings as .they are shown less plainly in these 

 species than any other studied. Such spots occur in some species of 

 Cicindela as for example campestris, aulica poly sit a, latrcillei (Fig. 

 257, PI. XIV) and ismenia (Fig. 366, PL XVI), which have a more 

 densely pigmented spot in the region of the sutural spots of other 

 species, i.e., in the position of C2.3 (Fig. 48, PI. V). In cleared elytra 

 of campestris a dark area appears at this point. Elytra of C. limbalid 

 (Fig. 127, PL X) shows this. In some cases dark spots appear at this 

 point in surface view ; in others metallic spots. When the dark color 

 occurs, the conditions described in page 51 are reversed — the surface 

 film is absent. The distribution of the chitinous columns above which 

 areas are first pigmented makes the study very difficult. The hairs on 

 the elytron which lie in the lines of the tracheae show pigment around 

 their bases by the end of 3 or 4 hours if not earlier. The elytron 

 reaches the adult color so far as pattern is concerned at the end of 

 about 15 hours, but pigment continues to be deposited for several days. 



Only one stage of C. sexguttata (Fig. 138) studied shows the spots 

 in the area between the tracheae faintly. Thef pigment is piled up 

 about the markings only to a slight degree. C. punctulata and sexgut- 

 tata belong to one of the Mexican groups and differ from the other 

 species studied. 



One specimen of Tetracha Carolina (Fig. 139, PL XI) was studied; 

 in this the pigment began to develop at the end of about 9 hours and to 

 manifest itself at the outer side of the elytron where it bends under, 

 and appears to move toward all parts of the elytron from there. A 

 somewhat lighter streak was left, however, between the costa and the 

 subcosta tracheae; this corresponds to stripe a, figure 139. The pig- 

 ment moves toward the inner angle but shows a lighter space at the 

 base between the ramus and the media and also a longitudinal stripe 

 between the media and the cubitus, which is broken at a point corres- 

 ponding with the dark band B between 2.3 and 4. This same break 

 occurs in the area between costa and subcosta. That portion of the tip 

 of the elytron between the media and the suture is the last to be pig- 

 mented. Figure 140, which represents the elytron at the end of 9 

 hours shows adult coloration. The darker dots represent the chitinous 

 columns over the center of which the primary pigmented cuticula is 

 thicker than any where else. At the point where it has been stated that 

 the pigment began developing the citicula is somewhat thicker than 

 elsewhere. 



