their prey, and were advancing to feize it. The 

 caterpillars of Fig. i. i. and 3. generally fix them- 

 felves to fome little ftick or itraw, Sec. that they 

 find in the water, and there remain, as I faid be- 

 fore, without ftirring. Thofe of Fig. 2. are more 

 frequently feen in motion among the thickeftpart 

 of the roots and plants that grow there, routine 

 and iearching for thofe fmall animals inhabiting 

 that part, which are their proper food. This aver- 

 fion to motion, lb apparent in thofe of N° I. and 

 3. appears to me to be the eft eft of an extraordi- 

 nary cunning and fagacity ; and may beconfider- 

 ed as the principal means by which they obtain 

 their prey : for while they continue thus motion- 

 lefs in the water, the fmall animals, who confti- 

 tute their proper food, approach them with lefs 

 fear than they would otherwife do, not fufpeeling 

 their grand enemy lies upon the watch to feize 

 them, the moment they come within his reach; 

 but no fooner has their infenfibility of danger 

 brought them within a fmall diftance of thofe de- 

 ftructive weapons (mentioned before, being placed 

 under their mouths) but that very inftant they 

 dart upon them with the utmoft rapidity, fudden- 

 ly throwing out their forceps, and feizing them 

 with as much eagernefs as a pike does the unwary 

 gudgeon : they then bring their forceps up to 

 their mouth with their prey in it, and feaft on 

 their captive prifoner. Nor is their voracious na- 

 ture lefs aftonifhing; and the greedinefs with 

 which the large ones feize other fmall animals, 

 would hardly gain belief among perfons entirely 

 ignorant of this ftudy. I have feen one of them, 

 in lefs than an hour's fpace, devour three infects, 

 each of which was full two-thirds as big as it- 

 felf ; but, in general, the fmall ones are the facri- 

 fices made by the greater; wherein I muft obferve, 

 that when they have got a caterpillar of the fmall 

 Libellas in their forceps, fuch as thofe of Fig. 1. 

 Plate 47. they leave no part uneaten, except the 

 three tails, which they let fall to the bottom, as 

 perhaps not having fubftance in them fufficient to 

 afford them proper nourifhment ; for as their food 

 conhfts altogether of animals lefs than themfelves, 

 tney neither fpare the caterpillars of the leffer Li- 

 bella, nor confine themfelves to thofe belonging 

 to other tribes. They will eagerly prey upon the 

 different kinds of Cads, or caterpillars of the Phry- 

 ganea ; great numbers of whom, at certain fea- 

 fons, quit thofe hufks or cafes they make and 

 fwim about, with lefs fear and dread than in the 

 early part of the fpring. I have alfo feen the ca- 

 terpillars of the Nota-nefias or Boat-flies, devour- 

 ed by them, and, not feldom, the fmall blood- 

 worms as they are called. In fhort, there are 

 but few of the lefler animals that live in the water,, 

 but when once they get within the reach of their 

 instruments, will certainly fall victims to thefe 

 freih- water Leviathans. I 



[ »9] 



petit baton ou paille, &c. qu'elles trouvent dans 

 l'eau, & s'y tiennent fans mouvement. Celles 

 de Pig. 2. font plus fréquemment vues en mouve- 

 ment dans les endroits, où les racines & les 

 plantes forment des buiffons épais, cherchant ces 

 petits animaux qui y vivent, & font leur proie. 

 Cette averfion au mouvement, fi apparente en 

 celles de N° I. & 3. me paroit être l'effet d'une 

 rufe & fagacité extraordinaire, & peut être confi- 

 derêe, comme les moyens principaux, par lef- 

 quelles elles obtiennent leur proie, car, durant 

 qu'elles continuent ainfi immobiles, les petits ani- 

 maux qu'elles maneent, les approchent fans peur, 

 n ayant aucune fufpicion, que leur grand ennemi 

 veille à les furprendre au moment qu'ils font dans 

 fa portée. Mais auffi tot qu'ils y font approchés, 

 étant infenfibles du danger, elles s'elançent fur 

 eux avec une grande rapidité, déployant leurs 

 pincettes ou forceps, & les prefiant avec autant 

 d'avidité qu'un brochet prefle le goujon, elles les 

 portent à leur bouche, & mangent leur victime ; 

 ni eft leur nature vorace, ni leur gourmandife, 

 avec laquelle les grandes faififfent les autres petits 

 animaux, à peine croyable, aux gens ignorans 

 dans l'étude des infectes. J'ai vu une, en moins 

 d'une heure, faifir & dévorer trois infectes, chacun 

 defquels, avoit au moins, deux tiers de fa propre 

 grandeur. Mais en générale, les petites en font 

 les victimes des grandes. Et il faut que j'ob- 

 ferve là deffus, que quand elles ont faifi une che- 

 nille des petites demoifelles, telles que Fig. 1. 

 PI. 47. elles ne laiffent de manger le tout, ex- 

 cepté les trois queues, qu'elles laiffent tomber ; 

 apparemment parcequ'elles n'ont point de fub- 

 ftance, propre à les nourrir ; comme elles fub- 

 fiftent entièrement fur les animaux, elles n'éparg- 

 nent point les chenilles des petites demoifelles, 

 ni fe repriment des autres efpeces. Elles man- 

 geront avidemment les différentes efpeces dePhry- 

 ganea ou friganes ; un grand nombre defquelles, 

 à certaines faifons quittent ces tuyaux qu'elles 

 forment, & nagent avec moins de peur, que au 

 commencement du printems. Je les ai vu auffi 

 dévorer les chenilles des Notaneâla ou Mouches- 

 bateaux, & non rarement les petits vers rouges 

 aquatiques. Enfin ces Leviathans, ne laiffent 

 echaper que peu d'infectes aquatiques, qui font à 

 portée de leurs pincettes. 



