MEANS OF DEFENCE OF INSECTS. 245 



his face with spirits of wine. This he observed was not 

 invariably the case with this beetle, its saliva at other 

 times being harmless. Hence he conjectures that its 

 caustic nature, in the instance here recorded, might 

 arise from its food ; which he had reason to think had 

 at that time been the electric centipede (Geophilus elec- 

 tt'icus). Lesser having once touched the anal horn of the 

 caterpillar of some sphinx, suddenly turning its head 

 round it vomited upon his hand a quantity of green vis- 

 cous and very fetid fluid, which, though he washed it fre- 

 quently with soap and fumed it with sulphur, infected it 

 for two days a . Lister relates that he saw a spider, when 

 upon being provoked it attempted to bite, emit several 

 times small drops of very clear fluid b . Mr. Briggs ob- 

 served a caterpillar caught in the web of one of our largest 

 spiders, by means of a fluid which it sent forth entirely 

 dissolve the great breadth of threads with which thejatter 

 endeavoured to envelop it, as fast as produced, till the 

 spider appeared quite exhausted . The caterpillars also 

 of a particular tribe of saw-flies, remarkable for the 

 beautiful pennated antennae of the males (Pteronus) d , 

 when disturbed eject a drop of fluid from their mouth. 

 Those of one species inhabiting the fir-tree (Pt. Pini) 

 are ordinarily stationed on the narrow leaves of that tree 

 which they devour rnosfc voraciously in the manner 

 that we eat radishes with their head towards the point. 



a Lesser L. i. 284, note 6. b DC Araneis 27. 



This gentleman is of opinion that spiders possess the means of 

 re-dissolving their webs. He observed one, when its net was broken 

 run up its thread, and gathering a considerable mass of the web into 

 a ball, suddenly dissolve it with fluid. He also observes, that when 

 winding up a powerful prey, a spider can form its threads into a broad 

 sheet. d Jurine Hymenopt. t. vi./. 8. 



