Mr. F. Walker on some new species of Chalcidites. 39 



quite distinct generations, of which one is homogonous, the other 

 heterogenous." Now we must distinctly deny that any such 

 case as this occurs : — There is no Polype yet known which has true 

 generative organs and also produces Medusiform bodies. It may 

 have one or the other, but never both ; and whenever the Medu- 

 siform bodies are developed, they represent the generative organs. 

 Xor is there any case known in which (as in Synapta) certain 

 individuals of a species of Polype possess generative organs 

 producing Polype ova, while others develope Medusiform bodies. 



It may be true that certain Medusa? arise from the ova of 

 other Medusa?, but this is no evidence of heterogony ; for we have 

 no right to assume, as is commonly done, that all Medusa? pro- 

 ceed from Polypes by gemmation. 



There is no evidence whatsoever in favour of the supposition 

 that the ova of Polypes may become Medusa?, but the con- 

 trary. It must then be admitted, that if Synapta possesses this 

 " heterogenous " generation, it stands alone as an instance of a 

 physiological phenomenon without analogy or parallel in the 

 animal kingdom. — Traxsl. 



V. — Notes on Chalcidites, and Descriptions of various netv species. 

 By Fraxcis Walker, F.L.S. 



[Continued from vol. vii. p. 216.] 



Megastigmus giganteus, Kollar MSS. Flavus, vertice thoracisque 

 disco viridibus, abdomine fulvo vitta fusca ornato, antennis 

 nigris, pedibus fluvis, tarsis anticis fulvis, alis subfulvis apud 

 stiff ma fusco maculatis. 



Fern. Head yellow, brown behind around the insertion of the 

 throat which is also yellow; crown bright green, with transverse 

 furrows which differ in size : eyes bright red : mouth tawnv : feelers 

 black, very slightly increasing in thickness to the tips, full as long 

 as the chest ; first joint long, linear, tawny ; second cup-shaped, 

 tawny, brown above and at the base ; third and fourth verv short ; 

 the following joints from the fifth to the eleventh long, linear, suc- 

 cessively decreasing in length ; club long-conical, full twice the length 

 of the eleventh joint : chest bright green, adorned here and there 

 with copper-blue and purple-colour ; breast and sides of the chest 

 pale tawny : fore-chest rather large, subquadrate, completelv sculp- 

 tured with transverse irregular furrows, which are one of the* charac- 

 teristics of the Torymidce ; its length more than half its breadth : 

 shield of the mid-chest very long, another peculiarity of this group ; 

 it is also deeply furrowed, but its fore-part appears' almost smooth, 

 the furrows being extremely small : sutures of the parapsides stronglv 

 marked, very slightly converging towards the hind-border of the 

 shield, and there parted from each other by much more than half the 

 breadth of the chest ; axillae separated by one-third of the breadth 



