Q6 HYDROPHIL. 



observed to prey on the smaller kind of water- 

 snails, and is distinguished by a particularity in 

 the highest degree remarkable: this consists in 

 the apparently anomalous situation of the legs, 

 which seem, unless very accurately considered, to 

 be placed, not beneath the thorax, as in other 

 insects, but on the upper part, and from thence to 

 be deflected towards the sides. This uncommon 

 appearance however is not owing to a real dorsal 

 insertion of the legs, but principally to the peculiar 

 shape and position of the head ; and the deception 

 is so much heightened by the inverted posture in 

 which the insect generally swims and rests, that it 

 is by no means easy, even for the most scientific 

 observer, to divest himself of the erroneous idea 

 before-mentioned. Frisch, in his History of In- 

 sects, appears to have been completely convinced 

 of the reality of the dorsal insertion of the legs; 

 and the celebrated Reaumur, having discovered 

 something similar in another aquatic insect, was 

 so struck with the unusual appearance, that he 

 has commemorated it as a circumstance unparal- 

 leled in the animal world. The author of the 

 fourth volume of Seba's Thesaurus was of the 

 same opinion, and expressly warns his readers that 

 his engraver, thinking to rectify what he supposed 

 an erroneous drawing, has represented the legs in 

 this larva as situated beneath the thorax and not 

 on the upper part. The sagacious Lyonet., in his 

 observations on Lesser's "Theologie des Insectes," 

 seems to have been the first who detected the 



