252 Dr. T. A. Chapman's 



but simply which is the end of the egg nearest the top of 

 the tube. 



Though a dissected beetle shows the tubules loaded 

 with eggs of all sizes, my observations go no further in 

 this direction ; it would be of interest to know whether 

 the eggs attain their full size before they are fertilised and 

 development begins, or whether they grow after develop- 

 ment of the embryo is begun. Probably not, but as the 

 embryos of the viviparous species grow considerably whilst 

 still in the tubules, only definite observation can determine 

 what happens in this species. 



When hatched the larva of 0. tristis is colourless, except 

 for the eyes, jaws, spiracles and the six black spots that 

 may be seen through the egg-shell, but it very soon 

 becomes quite black, with the exception of the fine brown 

 hairs which are plentifully scattered all over it. The head 

 and prothorax are at this stage exceptionally large, 

 forming fully two-fifths of the length of the larva. The 

 legs are nearly colourless and the under-surface is pale, 

 the larva is blacker than at later stages, the blackness but 

 encroaching a long way on to the ventral surface. 



The intersegmental depression divides the segment 

 deeply, but terminates some way above the spiracle, the 

 anterior and posterior subsegments meeting as a raised 

 ridge, below which the spiracle lies in a dejDressed 

 triangular area that extends to the front of the segment. 

 Length 2'0 mm., greatest breadth I'O m. 



At the first moult, i. e. in the second instar, the head 

 and prothorax remain dirty yellow for some time after the 

 abdomen has become black, and they remain a little paler 

 throughout the instar. The subsegments still meet in a 

 definite ridge above the spiracle, which is now hardly in a 

 depressed area, but has the diagonal grove separating 1st 

 and 2nd flange below it ; the anterior branch of the sub- 

 segmental incision exists, but is not at all pronounced or 

 visible in all attitudes of the larva, Length 3"0 — 4*0 mm., 

 width up to 2"0 mm., when contracted is almost a sphere 

 of ?;5 mm. in diameter. 



In the third instar the larva is very similar to the 

 second, the head and prothorax are still a little paler than 

 the abdomen. The branch of the subsegmental incision 

 is very short, but distinct in the 2nd instar, and is 

 very similar in the third. Length 5"0 — 8'0 mm., width 

 2*5 — S'O mm. 



