74-8 Retrospective Criticism, 



nicle)y and are inserted here because the first of the two para- 

 graphs describes a fact parallel to those described by Mr. 

 Spence. (p. 689.) — J. D, 



A Species of Spider evincing remarkable Habits. — Sir, 

 Having lately observed in this place a curious kind of spider, 

 I herewith send you an account of it. It seems to inhabit a 

 particular part only of the building ; and very much resembles 

 the small long-legged species found in our woods, only that 

 the body of the one now alluded to is oblong, instead of 

 round, as in the former. It appears always stationary in the 

 day, is without any web, and is generally in company with a 

 dozen or more individuals. It remains attached by its long 

 legs always to the ceilings, near to the sides of the building. 

 Its great peculiarity consists, when touched, in not moving, 

 but immediately commencing a whirling motion, so quick, 

 that it is quite impossible to see its legs singly. During this 

 Oiotion it never changes the position of its legs ; their length 

 and elasticity enabling it to continue this rapid whirling motion 

 for two or three minutes without cessation, as I have noticed 

 by my watch. If touched twice or thrice, it recommences this 

 carious motion, but with reduced force, until at last it ceases 

 it altogether. It is no doubt intended as a kind of defence 

 against its more powerful enemies ; for they may well be fright- 

 ened by this very unusual appearance. They roam about at 

 nights, no doubt, as I can never see them for two days in the 

 same place. I am, Sir, yours, &c. — H, B. Blois, France, 

 April 14. 1832. 



It is to be regretted that our valued correspondent did not 

 submit specimens of this interesting species to some naturalist 

 competent to make known its systematic name. — J, D. 



Spider^ s Thread. — The thread of the silkworm is so small 

 that many folds are twisted together to form our finest sewing 

 thread ; but that of the spider is smaller still, for 2 drachms 

 of it by weight would reach from London to Edinburgh, 

 400 miles. [Bristol Mirror, April 28. 1832.) 



Ichneumons from a Pupa of Lasiocdmpa quercus. — Mr. 

 Bree mentions (p. 106.) once obtaining more than 48 speci- 

 mens of a species of /chneumon from a pupa of the Lasiocampa 

 quercus, and there remarks, " I herewith send you spe- 

 cimens." These we have recently submitted to Mr. West- 

 wood's inspection, who (Oct. 13.) kindly replied: — " Mr.Bree's 

 ichneumon is a species of Pimpla, but I cannot now tell the 

 specific name. I have bred a species scarcely distinct, out of 

 Trichios5ma luc^rum." Was the species which Mr. Wood- 

 ward, in his communication on the Trichiosoma lucorum 

 (p. 85.), describes as destroying the pupas of that insect, iden- 



