66 THE ENTOMOLOGIST. 



opiuions, the learned authors cite the wondrous discoveries 

 of Cams, which seem opposed to them, and finally arrive at 

 this solution : — 



" The endeavours of M. Carus to discover any proofs of 

 a circulation in their last state, except in the wings at their 

 first development, were without success. He observes that 

 the fact of the currents of fluids in larva?, not being defined 

 by vascular parietes, enable us to comprehend the rapidity 

 and facility with which the traces of the circulation are lost 

 in the perfect insect. On the other hand, the existence of a 

 circulation at one period, and its cessation at another, 

 elucidates many circumstances connected with the physiology 

 of these animals ; for instance, the contrast between the rapid 

 growth and transformation of the larvse, and the stationary 

 existence of the imago, &c. Lastly, he remarks that the 

 phenomena of this circulation do not throw any light on the 

 obscure subject of the mode of nutrition in perfect insects ; 

 which, therefore, must still be supposed to be effected 

 according to the idea of Cuvier, — without the intervention 

 of vessels." — ^Introduction to Entomology^ vol. iv. p. ^Q. 



To Dr. Bowerbank we are indebted lor clearing up the 

 doubts about circulation. He attributes the errors, for such they 

 assuredly are, into which Lyonet and other great authorities 

 have fallen, neither to haste, nor inattention, nor inability, but 

 solely to the imperfection of the microscopes they employed. 

 After the publication of his paper in the fourth volume of 

 the 'Entomological Magazine,' troops of scientific men -came 

 to test, and of course ended in verifying, his observation : 

 Professor Owen, Marshall Hall, Newport, Gulliver, Mantel, 

 Geoffroi St. Hilaire. Of the last-named the following 

 reminiscence will be read with pleasure: — 



" One of the most remarkable of my visitors was the great 

 French naturalist Geoff'roi St. Hilaire, who paid a short visit 

 to England in 1833. He had read my paper 'On the Circu- 

 lation of the Blood in the Larva of Ephemera marginata,' and 

 doubted the possibility of seeing the valvular action of the 

 great dorsal vessel described therein. I had fortunately in 

 my possession some very favourable subjects for exhibiting 

 these beautiful phenomena; and when all was in order, and 

 the great man applied his eye to the instrument, he at once 

 saw the very facts he had doubted, and, without moving his 



