542 INSTINCT OF INSECTS. 



the pieces from the surrounding leaf before they proceed to set a stitch 

 into them. 1 



A remarkable instance of variation of instinct in the common house- 

 spider (Aranea domestica) is mentioned by an anonymous writer in the 

 Zoological Journal. He states that having placed one on a piece of wood 

 fixed in the middle of a glass of water, the spider, finding its other efforts 

 to escape ineffectual, enveloped its abdomen by means of its hinder legs in 

 a loose web which it spun, and then descended at once without the least 

 hesitation into the water, surrounded under its mantle with a bubble of air, 

 evidently intended for respiration as it included the spiracles ; and in this 

 extemporaneous diving-bell, like that of the water-spider (Argyroneta 

 aquatica) before described, it endeavoured to make its escape on every side, 

 but, on account of the slipperiness of the glass, in vain ; and after remain- 

 ing at the bottom of the water for thirteen minutes, it returned apparently 

 much exhausted, as it coiled itself under its wooden platform without mo- 

 tion. 2 As we cannot refer so philosophical a contrivance to reason, we 

 must regard it as a variation of instinct ; but certainly, if correctly reported, 

 a very curious one, as the occasions on which the house-spider can want to 

 escape through water must be very rare. 



In the preceding instances the variation of instinct takes place in the 

 same individual ; but Bonnet mentions a very curious fact in which it oc- 

 curs in different generations of the same species. There are annually, he 

 informs us, two generations of the Angoumois moth, an insect which has 

 been before mentioned as destructive to wheat : the first appear in May 

 and June, and lay their eggs upon the ears of wheat in the fields ; the 

 second appear at the end of the summer or in autumn, and these 

 lay their eggs upon wheat in the granaries. These last pass the 

 winter in the state of Iarva3, from which proceeds the first genera- 

 tion of moths. But what is extremely singular as a variation of instinct, 

 those moths which are disclosed in May and June in the granaries quit 

 them with a rapid flight at sunset, and betake themselves to the yet un- 

 reaped fields, where they lay their eggs ; while the moths whicii are disclosed 

 in the granaries after harvest stay there, and never attempt to go out, but 

 lay their eggs upon the stored wheat. 3 This is as extraordinary and inex- 

 plicable as if a litter of rabbits produced in spring were impelled by instinct 

 to eat vegetables, while another produced in autumn should be as irresistibly 

 directed to choose flesh. 



It is, however, into the history of the hive-bee that we must look for the 

 most striking examples of variation of instinct ; and here, as in every thing 

 relating to this insect, the work of the elder Huber is an unfailing source 

 of the most novel and interesting facts. 



It is the ordinary instinct of bees to lay the foundation of their combs 

 at the top of the hive, building them perpendicularly downwards ; and they 

 pursue this plan so constantly, that you might examine a thousand (proba- 

 bly ten thousand) hives, without finding any material deviation from it. 

 Yet Huber in the course of his experiments forced them to build their 

 combs perpendicularly upward 4 ; and, what seems even more remarkable, 

 in an horizontal direction. 5 



The combs of bees are always at an uniform distance from each other, 



1 Eeaum. iii. 112119. 



2 Zoological Journ. i. 284. 3 (Euvres, ix. 370. 

 4 Huber, ii. 134. 5 Ibid. ii. 216. 



