170 DR. V. E. SHELFORD ON THE LIFE-HISTORIES AND 



prothorax o£ the larvie of a given species are very constant. These, taken 

 with the other criteria just mentioned, leave little chance o£ error in 

 identifying the larvae of the species considered in this paper. Plate 26. 

 figs. 25-58 shows the distribution of bristles on the head and prothorax of 

 these species. The position of bristles that are sometimes absent is indicated 

 by a X . 



The first larval stage of C. purpurea (fig. 25) shows the usual type of 

 pilosity pattern of the first stage of the species here considered. The second 

 stage (fig. 26) possesses more bristles than the first and the arrangement is 

 here again very typical. The third stage (fig. 27) differs less from the second 

 than the second does from the first. The pilosity pattern of the larvse of 

 C. purpurea limhalis does not differ in any essential particulars from that of 

 purpurea. In the discussion of the succeeding species, attention will be 

 directed chiefly to the prothorax, the head presenting less interesting 

 differences in the different species. 



The distribution of bristles in the first stage of C. sexguttata (fig. 28) is 

 like that in the first stage of C. purpurea. The second stage may be 

 distinguished from that of C. purpurea by the presence of the bristles Y and 

 Z ; the third by bristle Z alone. Leng placed C. purpurea and C. sexguttata 

 in the same group ; his contention is borne out by these larval characters. 

 The first larval stage of C. punctulata (fig. 31) differs from the corresponding- 

 stage of the preceding species by the absence of bristle W (see fig. 28). 

 This structure is present in the second stage (fig. 32) in which the bristles 

 U and V are sometimes present also. The third stage (fig. 33) is subject to 

 considerable variation, but in case the pilosity pattern duplicates that of the 

 preceding species, the larva can always be distinguished by the size of its 

 head (Table III.). 



The first stage of the larva of C. repanda (fig. 34) lacks bristle W (see 

 fig. 28), but possesses bristles T and V (see fig. 32). Bristles V and Z (see 

 fig. 29) are usually present in the second and third stages (figs. 35 and 36). 

 The distribution in C. 12-guttata (figs. 37-39) does not differ in any essential 

 way from that in C. repanda. The bristles are usually larger and occasionally 

 bristle S (fig. 39) is present. 



The first stage of C. generosa (fig. 40) is like that of C. repanda (fig. 34). 

 The second stage (fig. 41) lacks the bristle V. The third stage (fig. 42) is in 

 some cases without those indicated by the X . The first stage of C. tranque- 

 barica (fig. 43) is hke that of C. repanda. The second stage (fig. 44) possesses 

 in addition to the bristles present in the second stage of C. repanda (fig. 35) 

 bristle Y (see fig. 29). The third stage often (fig. 45) does not possess 



bristle Y. 



The distribution in the first stage of C. scutellaris (fig. 46) is like that o£ 

 the four preceding races. The second stage (fig. 47) differs from the second 



