OF THE LARVA OF PYG/ERA BUCEPHALA. 187 



No. 35 in one specimen was di\ided into tlirec at the upper end. 



No. 37 is sometimes a good deal expanded at its upper end, and sometimes divided 

 into two. 



No. 38 in tlie same way is more or less divided at the upper end. 



No. 61 is more or less divided, the two main branches of which it consists being some- 

 times united for a large proportion of their course, and sometimes, on the other hand, 

 almost entirely separate. 



No. 52, which is usually single, was, on the contrary, in one specimen double. 



No. 56. This series of muscles varies extremely. There are usually from 7 to 11 fascicles, 

 but they were not alike in any two specimens I examined. 



No. 67 was douljle in the second specimen, and 



No. 58 in the fifth. 



Second Abdominal Segment. — The cases of varir.tion in this muscle are almost the same 

 as those already described. 



No. 1 in the fourth specimen was completely double. 



No. 10 in the second specimen was double for the anterior half. In the fourth specimen 

 10 and 11 were very smaU and united in front. In the ninth specimen 11 was double in 

 front. 



Nos. 12, 18, 14, 15, 27, 28, 29, 30, 81, 32, 33 and 84 offered various differences of the same 

 nature as those already mentioned ; besides which, in the fourth specimen, 14 was much 

 longer than 13 or 15. 



No. 26 was completely double in the second specimen. 



No. 38 was completely double in the fifth specimen ; in which also 



Nos. 40 and 41 were united by their lower ends. 



No. 54 in the eighth specimen was completely double. 



First Abdominal Segment.— T>ios. 12, 13, 14, 15, 27, 28, 29, 30, 31, 32, 33 and 34 differ as 

 much as usual. 



Nos. 10 and 11 are sometimes united in front, sometimes they only converge and do 

 not join. 



No. 18 in some specimens does not cover the fore end of 21. 



No. 37 in the fifth specimen is double. 



Third Thoracic Segment. — Nos. 12, 13, 14 and 15 differ as in the above-mentioned 

 segments ; 29, 30 and 31, on the contrary, are much more regular. 



No. 8 in the fifth specimen was completely double ; in the sixth it was double for the 

 greater length, but united in front. 



No. 20, in the ninth specimen, was double in front. 



Nos. 23 and 24 differed considerably in different specimens. The arrangement figured 

 is, however, perhaps the most usual. 



No. 62. This small muscle was in two cases entirely absent. 



No. 68 was double in two specimens. 



Nos. 59 and 60 are sometimes united ; in the fourth specimen they were separate on 

 one side, and had joined on the other. In the ninth specimen the posterior end of 59, 



VOL. XXII. 2 c 



