T887.I 177 



cutaneous endosmosis during this interval. At 4.30 to 4.35 p.m. the 

 first tracheae came suddenly into view. As the trachese were almost 

 invisible in some of the other larva?, I watched one closely, with the 

 view of noting the cause of their so suddenly becoming conspicuous, 

 when at 5.10 to. 5.15 p.m. I distinctly saw them injected, as I suppose, 

 with air for the first time. 5.15 p.m. : the filling of the tracheae 

 commenced in the posterior segments, a sort of cloud gathering at the 

 bend where it is close to the head, and in a line with the eye. I saw 

 an apparent]}] darh fluid start from this spot^ and creeping along with a 

 sort of spasmodic effort, filing the branches in its course, till it reached 

 the head, and the whole tracheae hecame conspicuously visible on that side 

 of the body. At 6.30 p.m. another egg was watched, which gave indi- 

 cations of the tracheae being about to be filled, in the shape of a dark 

 blotch, on the bend of the body, by one eye. The appearance of this 

 blotch is preceded by a dark cloud of granules from the annulus, which, 

 from the pressure of the growing larva, is forced here between the 

 head and the curve of the body, as the only part where it can find 

 access — and, I apprehend, it is now that the amnion is ruptured — 

 admitting air to the tracheae. Certain it is that after the injection of 

 the tracheae, it was in vain to look for any other envelope than the 

 outer one, or serous membrane. 9 p.m. : tracheae developed in all 

 except No. 2 egg. 11 p.m. : pulsations but little increased, at the 

 most, eight per minute. 



Eleventh day, 4.30 a.m. — Tracheae not yet to be seen in No. 2 egg. 

 At 7 a.m., by carefully examining, could define the margin of the am- 

 niotic sac in some parts of this egg still, as it must be 16 or 18 hours 

 behind the others. The mouth parts still hyaline in this one, but 

 chitinized in all the others, though even these do not appear yet to 

 have drawn in any yolk-granules by the mouth, a deal of motion going 

 on in the alimentary canal extending to the anal segment, which, at 

 9.15 a.m., was observed in one egg to have a motion of the anal flap, 

 as of suction, opening and shutting. 11 a.m. : soon after this, tracheae 

 appeared in the retarded No. 2 egg, and ingestion of yolk-granules 

 was first observed in the advanced ones. No. 1 especially, vigorously 

 drawing them down at 12.30 and 1 p.m., with a deal of motion of the 

 intestine, but granules do not appear to go further than end of crop, 

 where they are in a continual bubbling state. This condition of 

 things continued during the afternoon; pulsations not much increased, 

 8 to 12 per minute, but difiicult to count from the other incessant in- 

 ternal motion. 7.30 p.m. : the hairs appearing faintly in the advanced 

 ones. 9 p.m. -. serous membrane traceable in most of the eggs, but 



