f 



1912.] 31 



tergite. He only mentions one process on each side, iny specimens show 

 two. Mayet describes the outer one as an anchor, the inner as a spin- 

 neret, and says these reach the surface of progression (hair of bee, &c.) 

 by the incurvini^ of tlie further segments, like those of a lobster. 

 Fabre notes the secretion of some gummy substance, but ascribes its 

 origin to the anal extremity. 



No such structure appears to exist in Meloe or Metoecus. The 

 photographs will give some idea of its appearance and position. 



It is the tenth abdominal segment that carries the long terminal 

 bristles. In the photograph, the seventh, eighth, and ninth segments 

 show, on the left side, what are possibly the spiracles, of which 

 Newpoi-t. says there is one on the ninth segment in Meloe. 

 Metcecus paradoxus, L. 



The young larva of Sitaris revives my memories of the early stages 

 of Metoecus paradoxus, of which I once saw a first stage larva at large, 

 without at the time knowing what it was.* It is very like that of 

 Sitaris, but only about half the size. No one has since taken the 

 trouble to obtain it. There should be no difficulty aboiit this, wasps' 

 nests, taken at the right season, will supply sufficient imagines to provide 

 pairings and ovipositings if suitable conditions are provided, viz., 

 flowers and simshine, and wood well-cracked, but not actually rotten. 

 The photographs reproduced (from specimens some 40 years old) show 

 the first stage laiwse when, having fed in the interior of the wasp-grub, 

 they have grown so as to separate their dermal plates. Another photo- 

 graph shows the front of a wasp-grub after the Metoecus larva has 

 become external. It shows the dermal plates of the cast skin, irregu- 

 larly piled together, where it blocks the hole of emergence in the skin 

 of the wasp lai-va. The object of the photograph is, however, to present 

 a record of the place of emergence ; to do this, the imaginal legs of the 

 pupa are displayed. These are still imder the larval skin, a grub 

 attacked by Metaicns never assuming the pupal state, though the 

 preparations for doing so, and casting the larval skin, proceeds so far 

 as to make the legs shown in the photograph immistakeable. To 

 display them some little disturbance has taken place, but it can be seen 

 that the cast skin is medio-ventral «)n the third thoracic segment. 



The legs are of interest as showing the three-jointed tarsi, with 

 lateral expansions, possibly in relation to seeming a hold on the smooth 

 skin of a wasp, so different from the hairy coating of a bee (though a 

 wasp is not by any means hairless), They contrast with the simple 



"Annals and Mag. Nat. Hiat., September, 1S70, pp. 101--J04. 



