GENITAL SYSTEH OF LTCTUS BRUNNEUS. 589 
on reconstructions made from a series of longitudinal sections of a fertilized 
female, and depict a left and right lateral view respectively, with the upper- 
most ovary and oviduct removed in each case. Fig. 2 is based on recon- 
structions made from balsam mounts of cleared specimens and from dissections, 
and depicts a dorsal view in which the relatively greater length of the rectum 
(?■) of the female in comparison with that of the male (PI. 31. fig. 4, r) is 
made apparent. The ratio is approximately 30 : 1. 
PI. 32. fig. 2 shows in longitudinal section the dorsal [djy) and ventral (vp) 
pygidial plates with the apex of the " ovipositor " between, and also part of 
the 7th sternite (VII), i. e. the Tjth sternite of systematists. 
The functioning of the parts of the ovipositor appear to be as follows : — 
In repose (PI. 32. fig. 1) m', nr, and ??i^ muscles are in a state of con- 
traction, whilst m' and the longitudii^al series within the inner sheath are in 
a state of expansion. By the contraction of m', the outer sheath commences 
to collapse, the distal portion to issue from between the pygidial plates and 
drawing with it the muscular rectum and the common oviduct. By the 
simultaneous contraction of the muscles within the inner sheath, the outer 
sheath is caused to evaginate and issue from between the pygidial plates. 
The outer sheath continues to evaginate and issue until brought in check by 
»i' muscles. When fully extruded the " ovipositor " is approximately the 
length of the female. 
The withdrawal of the ovipositor is apparently achieved by the contraction 
of the expanded m* muscles, aided by the muscular common oviduct, which 
would pull back into its position of repose, bringing the distal portion of the 
"ovipositor" with it. Simultaneously, the contraction of ?n' muscles- would 
pull back the basal part of the outer sheath, whilst m^ muscles would draw 
into position the apical portion of the sheath. 
As there are no muscles attached to the ileum, the colon, or the rectum, 
the resumption of the position of repose for this portion of the alimentary 
tract must be solely dependent upon the slight contraction of which the 
muscular rectum is capable — aided by the fixed mesenteron — and any 
tension that might be exerted by the ramifications of the trachea. That such 
is apparently the case is shown in PI. 34. fig. 2. Here, the rectum is seen 
convoluted — a condition that can only be attributed to an imperfect 
musculature. 
Other sections of the same beetle disclosed two other points within the 
"ovipositor" where the rectum was similarly convoluted. In this condition 
no beetle could defsecate unless it extended its " ovipositor," and thus 
straightened the rectum. Whether this is ever done is not known. But as the 
food of these beetles consists of particles of wood, most of which appears in 
the f rass never to be broken down, it is possible that penetration of the walls of 
the rectum and of those of the common oviduct may take place. And it seems 
probable that this defectiveness may be the cause of the death of quite a 
