286 Mr. A. White on the Pupa-case of a Coleopterous Insect. 



were flat, greyish brown, of an oblong form, strangulated some- 

 what in the middle and rounded at the end, — much like the 

 pods of one of the Cruciferm in our gardens (an annual or bi- 

 ennial), whose seeds have flat rims, assisting to disperse the seed, 

 or to buoy it up for a time, till at last it sinks. These pods 

 looked also a little like two somewhat roundish flat ovals con- 

 nected, with a distinct and smoother oval impression on the 

 middle ; they were formed of minute particles of yellowish and 

 brownish matters, closely cemented ; their outline was a little 

 irregular; and they were not all shaped exactly alike. I put 

 them away. On being approved by our Keeper, and recom- 

 mended, the North China insects, like all the specimens of zoo- 

 logy, were ticketed and marked. What was my surprise to see 

 a pair of pectinated antennae and a head poking out from each 

 of them ! I did not see this when first I took them ; and I am 

 almost sure that the Coleopterous insects, whose heads they 

 were, had emerged from the pupae during the month or six weeks 

 that had elapsed between the selection and the ticketing of these 

 specimens. I opened one, and found it like the two valves of 

 some bivalve shell, such as Psammobia. The inside was very 

 smooth, and nicely lined with some insect secretion. Mr. Min- 

 tern's figures (PI. VII. figs. 1 a%c\d) will show this structure. 

 Before entering on the description of the Beetle which constructs 

 it, and which is figured on the plate (fig. 1 ), I may quote a 

 passage from a note kindly sent me by Dr. Bowerbank, a friend 

 who examined the structure with his well-exercised eye and 

 mature judgment, and gave me the results of it in the following 

 words : — 



" My dear Sir, — The insect and its case, which you placed 

 in my hands for examination, is a very interesting subject. 



" The case is evidently constructed of pellets of excretions 

 worked into a uniform stratum, with the intermixture of a few 

 masses of extraneous matter, which may generally be distin- 

 guished from the deep-brown semitransparent globules of excre- 

 ment by the difference of their colour, and their being more or 

 less angular. 



" The interior of the case is lined with extremely fine silky 

 fibres -qoVt ^^^^ ^^ diameter; they are disposed in curved 

 bundles of parallel threads, crossing each other irregularly, so 

 as to give the appearance of being fitted on to the surface, — the 

 aspect of the whole being just such as would be produced by the 

 larva spinning from its mouth a fine viscid thread, and fixing it 

 by motions of its head right and left. 



" Most truly yours, 



" J. S. Bowerbank.^' 



