18f.8.] 



17 



one is preferable, at another another ; that which is most suitable for one species 

 may be objectionable in the case of otlicrs. In selecting our soil we should be 

 gnidecl by the natural habits of the species for whose benefit we are cogitating, the 

 nature of the soil which it naturally inliabits, the position, wet, dry, hot, cold, east, 

 west, south, &c., which it naturally selects for its tr;insformation. 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. AH soils should be first 

 well baked to destroy animal life (such as acari, slugs, eggs of lai-vaj of Tineoe, 

 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 covei^ed 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 larvae as spin up, the most approved appliances have been already 

 noted under the heading " cages." 



(To he continued.) 



Note on Agabus offinis, PayTc.— 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 efi"ect that all Mr. Crotch's examples of Agahus affinis 

 belong to the newly-described Eriglenus unguicularis 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 Agab tis affinis as the affinis of that author. 



I have, however, just captured four specimens of an Agahus so closely resembling 

 my series of aflnis 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 Tlriglenus unguicul vris. 



I hope the following characters may help entomologists to distinguish the two 

 insects. Being of about the same size, A. affinis is rather narrower in proportion 

 to its size than A. unguicularis ; it is of a more parallel 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 laciniae of 

 the metastemum. Besides these characters pointed out by Thomson, which are 

 certainly not veiy 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 unguicularis, while it is quite 

 black in affinis. I should add, that affinis is altogether of a darker and blacker 

 colour than the brassy-black unguicularis. Closely allied as these two insects are, 



