232 Transactions of the Society. 



case of Damseus geniculatus and D. clavipes; the egg in these 

 species is an oval somewhat flattened on two sides ; it is brown, but 

 round the edge runs a lighter band where it seems that the shell is 

 thinner ; along this band the shell breaks, finally separating into two 

 boat-like pieces ; it breaks first at the small end, which contains the 

 head, or rather rostrum, of the larva; the long legs are doubly- 

 folded upon the under side of the body; the long hairs of the back lie 

 flat and pointing straight backwards ; the front part of the cephalo- 

 thorax, when I watched the process, protruded first ; it was slowly 

 followed by the anterior pair of legs ; then the whole cephalothorax 

 aud the second pair of legs gradually made their appearance, the 

 progress being very slow ; a long delay then seemed to take place, 

 during which the various parts stifiened and assumed their normal 

 positions, the hairs becoming more or less perpendicular ; the hinder 

 pair of legs (for the larva is hexapod) remained in the shell until 

 the last, and pushing against the inside of one half, while the back 

 rested in the other, seemed slowly to open it. As the difierent 

 parts emerged, everything movable was kept continually moving, a 

 strange sight in these slow and lazy creatures; the legs were 

 worked in all directions, and it was amusing to watch the parts of 

 the mouth constantly going ; the lobster-like mandibles, usually so 

 difficult to see, were protruded and retracted independently, and 

 kept snapping continually. The escape from the egg lasted six or 

 eight hours ; I cannot say if it takes as long in a state of nature. 



The change from the larval to the nymph stage does not offer 

 any sufficient difference from that from nymph to perfect creature 

 to make it necessary to describe it. Claparede {loe. cit.) in his 

 admirable papers on the Acarina describes how he watched the 

 transformations of water mites of the genus Atax, and found that, 

 on the change from larva to nymph and from nymph to perfect 

 creature, it was not a mere change of skin that was eff'ected, but 

 that the whole creature dissolved, the new creature being formed 

 from the material, the skin of the old creature coming away and 

 leaving an egg-shaped body, long before the new creature was fully 

 developed. More lately Megnin has traced the development of the 

 Sarcoptidss and Gamasinm with precisely the same result as 

 Claparede. 



I am not aware that anyone has previously watched the 

 Orihatidee, but my own observations upon them certainly lead me 

 to the same conclusion. It must not, however, be forgotten that 

 Duges, in his excellent chapter on the Hydrachnidm, the trans- 

 formations of which he watched, expresses a contrary opinion, and 

 says that the creature retires within its own skin as within a bag, 

 and that the parts are modified rather than newly formed ; and he 

 says, in support of this view, that mutilated parts do not reappear. 

 Probably the real divergence of opinion is not so great as it seems, 



