of the Circulation of the Blood i?i Insects. 49 



Anatomy of Animals, 1827), of a distinct circulation of the 

 blood in insects; and having had the advantage, within these 

 few days, of witnessing some of the most striking facts upon 

 which his discovery rests, which he had the goodness himself 

 to show and explain to me, I am anxious that your entomolo- 

 gical readers should partake of the high gratification which 

 this interesting sight imparted to me; which any one might 

 enjoy, who will examine some very common insects with a good 

 compound microscope. 



The first insect to which Dr. Cams directed my attention 

 was the larva of Ephemera vulgata (or an allied species), in 

 which, near to the branchiae and parallel with each side of the 

 body, was very distinctly visible a constant current, towards 

 the tail, of oblong globules swimming in a transparent fluid, 

 propelled with a regular pulsating motion ; and on cutting the 

 body of the larva across near the tail, these globules were most 

 plainly seen pushed out of the divided vessels in a distinct mass, 

 which increased at each pulsation. I cannot express the plea- 

 sure which it gave me to see thus clearly this ocular demon- 

 stration of one of the most important physiological discoveries 

 of modern times; and my gratification was heightened by the 

 next object which Dr. Carus placed before his microscope, viz. a 

 specimen of Semblis viridis, in which precisely the same phe- 

 nomena, but if possible more clearly, were §eenin the nervures 

 of the wings and in the antennae, in both which the constant 

 current of globules was most apparent; and in the former, the 

 sudden turning of these glpbules at the apex of the wing, out 

 of the. exterior nervure into a central one, with which it joins 

 and fprjEns an acute angle, was equally curious and striking. 

 On cij,ttirjg off the end of the antennae, precisely the same 

 emission of globules (which soon assume a greenish tint) took 

 place as in the former case, forming a mass which was increased 

 with a sudden gush at each pulsation. 



Dr. Carus has observed the same phenomena in the wings 

 of Semblis bilineata, and in the elytra of iampyrisnoctiluca and 

 L. italica, .as well as in the fin-like appendages at the tail of 

 the larva of A^grion puella, in which he first made the discovery, 

 and in which the circulation is remarkably distinct. 



The only point of manipulation in examining the specimens 

 which it is necessary to notice is, that Dr. Carus places them 

 on the slip of glass, not in mere water, but in a drop of pretty 

 thick gum water, which confines their too agile movements 

 without injuring the transparency of the medium. 



I mugt not omit observing, that when Dr. Carus was in 

 Italy last year, he made some new and curious observations 

 relative to the connection which exists between the circulation 



Vol. III. — No. 11. e 



