VARIETIES. 531 



of the Belfast Natural History Society for January, 1834, con- 

 tain a notice by Mr. Robert Patterson, V. P. of the discovery 

 of an unusual inhabitant in a fresh water shell ( Limnceus 

 .pereger). When the shell was taken out of the pool, its 

 mouth was stopped with what appeared a mass of clay ; but 

 proved to be a fragment of some aquatic plant of suitable length, 

 the space between it and the margin of the aperture being filled 

 with slime. The interior of this mass was lined with a soft, 

 whitish, silky substance, which extended to the margin of the 

 aperture. The chamber was occupied by a living individual of 

 Gyrinus villosus. Nothing was observed by which the object 

 of this occupancy might be explained. A member of the So- 

 ciety, Mr. G. C. Hyndman, referring to the habits of G. natator 

 which is transformed in a silken cocoon, suggested that the 

 larva of G. villosus might have taken possession of an empty 

 shell in which to undergo its change, and that the beetle found 

 in it might be recently disclosed ; but the fact, that the cocoon 

 of the former is suspended above water, is unfavourable to this 

 view. 



Qiusre ? Is this an accidental occurrence, or does it indicate 

 a peculiarity in the habits of this Subgenus ? 



A. H. Haliday. 



53. Psychoda nervosa. — T have bred this insect in great 

 numbers from putrescent Boleti. 



A. H. Haliday. 



54. Chlorops Uneata. — This insect is always very abundant 

 in houses during the spring and autumn ; but in September 

 and October last it quite darkened the ceilings and windows in 

 Middlesex and Hertfordshire with its innumerable hosts, and is 

 common, even now, in December. The larva is unknown. — N. 



55. On the Husk in Cattle. — Sir, Having a disease 

 among my young cattle which appears but little understood, at 

 least in this part of the country, and which threatens to be 

 somewhat formidable in its effects, I am induced to communi- 

 cate, as far as my observations enable me, although the results 

 have not been satisfactory, some account of it ; partly for the 

 benefit of those who may have seen less, and partly to solicit 

 information through your useful columns, from those who may 

 have seen more of the disease than myself. It first made its 



