1868.] 17 
one is pi-efeiable, at auother anothei' ; that which is most suitable for one species 
may be objectionable in the case of others. In selecting our soil we should be 
guided by the natural habits of the species for whose benefit we are cogitating, the 
nature of the soil which it naturally inhabits, the position, wet, dry, hot, cold, east, 
west, south, &c., which it naturally selects for its transformation. For the rest I 
must leave the choice to the reader, merely contenting myself with an enumeration 
of the most approved kinds : leaf-mould — sand, silver-sand, or " ballast," the latter 
is however apt to " cake " — loam — the rubbish from the roots of oaks and forest 
trees, rotten wood, bran, cocoa-nut fibre — birch catkins (rubbed between the hands 
into light flakes) or combinations of two or more of them. All soils should be first 
well baked to destroy animal life (such as acari, slugs, eggs of larva) of Tinece, 
spiders, wire worms, &c.), they should then be placed in closely fastened canvass 
bags, damped, and kept in a moist situation until required for use. Where it is 
required to keep up a certain degree of moisture, the soil should be covered with 
damped moss or a layer of cocoa-nut fibre, the latter being a capital means of pre- 
venting the soil beneath from becoming too dry. 
For such larvas as spin up, the most approved appliances have been already 
noted under the heading " cages." 
(To he conti7iued.) 
Note on Agahus affinis, Paylc.—In this month's "Entomologist" Mr. G. R. 
Crotch has published a most interesting list of certain of Thomson's additions to 
the Swedish Fauna, accompanied by a few remarks which, while indicating a great 
deal of research, are far too concise for those who like Entomology made easy. 
Among them is one to the eS"ect that all Mr. Crotch's examples of Agahus affinis 
belong to the newly-described Eriglenus ungidcidaris of Thomson. I had within 
the last few weeks examined my Hydradephaga with the assistance of Schaum's 
recently published posthumous work, and had, satisfactorily enough, considered 
all my British examples of Ag obits afinis as the affinis of that author. 
I have, however, just captured foar specimens of an Agahus so closely resembling 
my series of affinis that only an educated eye would notice any difference of facies ; 
and, on consulting Thomson's work, I have satisfied myself that these four speci- 
mens are to be referred to his Oaurodytes affinis, while all my other specimens 
must, like Mr. Crotch's, be considered Eriglenus unguicul.iris. 
I hope the following characters may help entomolofrists to distinguish the two 
insects. Being of about the same size, A. affinis is ratlier narrower in proportion 
to its size than A. unguicidaris ; it is of a more pai'allel form (the sides of the 
thorax behind, and the sides of the elytra, being straiter and less rounded), the large 
punctures on the elytra are more evident towards the base in affinis, and there is 
some (though not a very considerable) difference in the shape of the lacinire of 
the metastemum. Besides these characters pointed out by Thomson, which are 
certainly not very easy to appreciate, my specimens show another by which the 
species can readily be distinguished, viz., that the broad turned-under margin of 
the base of the elytra is of a rather obscure red in ^^ng^licltloris, while it is quite 
black in affinis. I should add, that affinis is altogether of a darker and blacker 
colour than the brassy-black unguiciilaris. Closely allied as these two insects are, 
