20 ILLIXOIS BIOLOGICAL MONOGRAPHS [414 



Varica Herbst is seen to be made up of Al, A2, B3 {humeral luniilc) ; 

 A4, B4, B5, Co {middle hand) ; and A6 and 7 {apical lunule). In figure 

 31 may be noted the forward hook-like extension on the so-called 

 humeral lunule which represents B2, the union between B5 and C6, etc. 



Figures 61 to 72, plate VI indicate some of the commoner combin- 

 ations of spots. Figure 66 shows a union between the humeral lunule 

 and A3 ; figure 70 a combination of 7, with B6 and B5 which are connect- 

 ed with the central cross band ; figure 71 a cross connection in baud 2-3 

 between stripes A and B ; figure 72 a cross connection in band 4 between 

 A and B ; figures 76 to 77, plate VI show the reduction of cross bands 

 to large spots. Thus the conclusion that the patterns are derivable from 

 combination, loss, and extension of a number of inter-tracheal spots fall- 

 ing in cross rows seems justified. There are various types of combina- 

 tion and extension which are not common when the group is considered 

 as a whole, but which represent tendencies in certain isolated groujjs of 

 species and which must be illustrated (Figs. 78 to 98, PI. VII) here 

 because they othewise appear to be obstacles to the plan. One of these 

 tendencies is one toward oblique combinations indicated in' figure 78 

 (a diagram). One type indicated by the wide stippled band is shown 

 in figure 79, a South American species. A similar combination occurs 

 as a variation in an Indian species (Fig. 80). A more gentle sweeping 

 combination is shoA\Ti by the narrow white line in figure 78 and occurs 

 as the regular pattern of an African species (Fig. 81) ; shorter curves 

 occur in another African species (Fig. 82). Other oblique combinations 

 are shown in figiires 83 and 84. The type of obliqueness shown by sev- 

 eral African species (Figs. 85 to 87) is an oblique shifting of the entire 

 pattern ; it appears to be turned parallel to the end of the elytron. This 

 appears to be a significant tendency and will be discussed again in con- 

 nection with the discussion of experimental results. 



Figures 88 to 91 show a tendency toward obliqueness of markings 

 reversed as compared with that just described and characteristic of the 

 princeps-cylanensis gi-oup of India and Africa. It may be said to char- 

 acterize the patterns of a group standing apart from the other represen- 

 tative of the genus. 



Figures 92 to 95, plate VII show unusual sinuate extensions of the 

 markings. In figures 92 and 93, Indian and Australian species, a mark- 

 ing resembling the usual "middle band" arises in the area A2.3 with a 

 form similar to that found in figiires 94 and 95. Figure 96 shows bands 

 5 and 6 separate toward the outer margin of the elytron and united 

 toward the inner. Figure 97 shows unusual extensions of the markings 

 giving two light bands between the tracheae (compare with Fig. 19, PI. 

 II) ; 98 shows unusual direction of extension. 



From the preceding discussion and diagrams I concluded that even 



