188 MR. LUBBOCK ON THE CUTANEOUS MUSCLES 
instead of lying at the side of 60, was inserted under, that is to say, at the outer side of 
it. In two specimens there was a small muscle lying at the dorsal side of 59. 
No. 61 is sometimes simple behind, sometimes divided. 
I now proceed to compare the muscles of Pygæra with those of Cossus ligniperda, as 
described by Lyonet, and of one or two other insects which I have more or less com- 
pletely dissected. 
The following Table shows the letters and numbers used for the corresponding muscles 
in the abdomen :— 
1=A 1624 sant 46 = 
2=.B 17.2536 Re 47 = »y 
5 = C Ig me uS ¿ 48 = 
4=D 9=f uc] 49 — 
5G 20 = e Bi " 50 = 8 
6=E 21 = a ur) 51 = 
7=H 24cm yo 02 m. 
8=F 28 =f 39 2. [^ | 53 = „Sin the first figures 
ger E 24 = | 39 — I (part) ex Ur 
Tesi: 25 =f | 40=m 54 = 
11 = 26 =} ee at? 
ms Hai | 42 T 56 absent 
= =p 43 = 57 = 
14= (Q 20. nue + un he 
15 = 30 | " 45 = 1 (part) 
Thus, with very few exceptions, every muscle of the third abdominal segment in Pygera 
can be referred to its homologue in Cossus. 
There are, however, some few differences: B in Cossus is only as long as the segment, 
_ as is also the case in the larva of Pontia rapi ; while 2, the corresponding muscle in Pygera, 
has united with the same muscle of the two preceding segments,—the three together 
forming only one muscle as long as the first three abdominal segments. 
: Again, G shows traces of subdivision, and is covered in part by F, while 5 is single, and 
lies on the dorsal side of 8. I also is treble, while 9 is single. L is treble, while 10 and 
11 only form two muscles; on the other hand, Q is only treble, while the series from 12 
to 15 is quadruple. 
€ crosses over ff, so as to cover it behind instead of lying at the side of it. % does not 
seem to be present in the third abdominal or any of the posterior segments of Pygera, 
and only makes its appearance in the second abdominal segment. 
There seem to be three fascicles, marked Z, to correspond to 33 and 34; and 35 and 36, 
which are marked 6, are represented by several fascicles. 
First and Second Abdominal Segments.—In these segments there are no further differ- 
ences of importance. 35 and 36, however, which in Pygera are reduced to a single 
muscle, continue in Cossus compound as before. 
Nos. 46, 47, 48, 49 
f and e resemble 1 
