692 Nets of the commoji Garden Spider, 



viscid materials than its suspensory lines ; a circumstance 

 alleged to be proved by the former appearing under the 

 microscope studded with globules of gum.* We have not 

 been able to verify this distinction, having seen the suspensory 

 lines as often studded in this manner as those in the centre." 

 [Insect Architecture, p. 360.) 



This remark, I confess, I read with no small surprise. 

 Having, in writing an account of these nets for our book, 

 found nothing satisfactory respecting them in former works, 

 I resolved to describe them wholly from my own observations, 

 in which I spent great part of many days, repeatedly watch- 

 ing the whole process of the construction of the net, from the 

 stretching of the first main Hue to the completion of the last 

 spiral ; and it was in the course of these observations that 

 my attention was first directed to the remarkable difference 

 between the lines of the rays and of the circles, depending on 

 the presence of these globules of gum only on the latter, which 

 I examined again and again, that I might be sure of being 

 correct in an observation which seemed to have escaped for- 

 mer writers, and which struck me as being very singular in 

 itself, as the spider must either be furnished with two differ- 

 ent sets of silk vesicles, one for secreting the ungummed silk 

 of the rays of the net, and the other for the gummed silk of 

 the circles ; or, which would be equally curious, it must pos- 

 sess an apparatus destined for studding its ordinary line with 

 drops of gum solely when this line is employed in forming 

 the circles of its net. 



With such grounds for inferring the accuracy of my ob- 

 servations, I had little doubt that, if Professor Rennie had 

 been unable to verify them, the fault lay with himself; but, to 

 be quite certain that some optical illusion had not deceived 



" * Kirby and Spence* s Intr.^ vol. i. p. 4 19." Here Professor Rennie refers 

 to our work as a joint production ; but in various other instances he 

 adverts to it, for what reason I know not, as if written by Mr. Kirby alone. 

 I am ignorant on what process of divination Professor Rennie has founded 

 his competency to attribute to each individual author the facts recorded in 

 a joint production, but the result is what might have been expected from 

 such an attempt ; a large proportion of the facts and observations thus 

 ascribed by him to my excellent friend and associate having been made and 

 described by me : as, for example (to omit various other instances), the 

 experiment with Epeira diadema {Insect Architecture^ p. 340.) ; that with 

 the group of gnats' eggs {Insect Transformations, p. 74.); the observation 

 as to the destruction of aphides by the larvae of the Sjrphidae {Ibid., 

 p. 270.) ; and the description of the transformation of Chironomus plu- 

 mosus {Ibid., p. 319.): which last I notice for the purpose of observing 

 that Professor Rennie would not have put the query in the note, as to the 

 power of the thorax to repel water, if he had considered for a moment 

 what takes place with a floating needle, which instantly sinks if a drop of 

 water be let fall on it. 



