74 Mr. S. S. Saunders's Descriptions 



These larvae are found occupying spacious elongate-oval cells, in 

 galleries containing a series of such receptacles, from which the 

 entire pith has been removed ; with intermediate spaces of vary- 

 ing dimensions, partly filled with mud and partly with compressed 

 particles of pith in sectional divisions; each cell being first se- 

 curely closed by a well-connected convex top of firm pergame- 

 neous consistency, followed by a small portion of black mud. 



The store provided by the parent-insect, judging from the re- 

 mains occasionally found about the cells, consists apparently of some 

 small yellow-headed larvae, which Mr. Westwood considers to be 

 Coleopterous, and probably to belong to some species of Curcu- 

 Uonidce ; after consuming which, the full-fed larva remains as 

 usual during a considerable period in an inert state, assuming the 

 condition of a fully-developed pupa a few weeks only previously 

 to its final metamorphosis towards the middle or end of June. 



These pupae are endowed with the singular faculty of exe- 

 cuting a rotary motion when disturbed, by bringing the apex of the 

 abdomen into play around the bottom of the cells, performing 

 these revolutions for a number of times in rapid succession, the 

 direction being occasionally reversed. A similar proceeding on 

 the part of a species of Ichneumon (hence termed gyrator) is 

 described by MM. Dufour and Perris in the Annales of the 

 French Entomological Society.* 



The perfect insect effects its exit by gnawing a circular aperture 

 through the side of the briar, for which operation its powerful 

 serrate mandibles are well adapted. 



The dark brown corneous case of a species of Chrysis is not 

 unfrequently found in the cells, closely enveloped in a thin tissue 

 covering of its own. 



Of the second species males alone were obtained from a briar 

 which had been confounded with others occupied by the larvae of 

 R. Eumenoides. With these, however, I have not hesitated to as- 

 sociate a female, possessing all the characters of the genus which 

 I captured, flying along a sandy road, another having subse- 

 quently been found among a miscellaneous collection of briars ; 

 and, unless properly referred to this species, the latter would 

 constitute a third. 



* Vol. ix. p. 43, 1840. 



