62 Mr. J. O. Westwood's Notes on the 



nearest to the posterior margin. Through the central connecting 

 transverse ribs blood also passed from the proceeding to the 

 returning current." Burmeister then enters into lengthy details, 

 both structural and physiological, the result of which is that 

 although the ribs, as the translator calls them, contain tracheae, or 

 air vessels, the latter are enclosed within a vacant space, in which 

 the juices can freely circulate (p. 412). 



Newport, again (article " Insecta," in Cyclop. Anat. and 

 Physiology, p. 112), after stating the observations of Carus, Bur- 

 meister, Tyrrell, Wagner, and especially Bowerbank, in the En- 

 tomol. Magazine, vol. 1, p. 243, as well as observations of his 

 own, proceeds, " From these facts we are led to express an 

 opinion, which has been long entertained by us, that the course of 

 the blood, whether simply along intercellular spaces, or bounded 

 by distinct vessels, is almost invariably in immediate connexion 

 with the course of the tracheae. This opinion is founded upon 

 the circumstance that nearly all the observations that have 

 hitherto been made have shown that the currents of blood in the 

 body of an insert are often in the vicinity of the great tracheal 

 vessels, both in their longitudinal and transverse direction across 

 the segments, and it is further strengthened by Mr. Bowerbank's 

 observations on the course of the blood in the wing." After de- 

 tailing these observations, he concludes, " These observations are 

 exceedingly interesting in reference to the general velocity of the 

 circulation, and the means by which it is carried on in the wing. 

 The entire absence of pulsations is remarkable, as it completely 

 identifies these vessels as veins, since it is well known that the cir- 

 culation is carried on through the body by means of regular pulsa- 

 tions of the dorsal vessel. 



Such are the considerations which induced me, in my portion of 

 the " Genera of Diurnal Lepidoptera," to employ the term vein 

 for these organs, and to assert that physiological investigations 

 had proved them to be such. 



But Mr. Newman (after demolishing a phantom of his own 

 creation, in the shape of a nerve hypothesis, every writer who had 

 employed the term nervure having expressly guarded himself 

 from the implication of an inferred identity between the functions 

 of true nerves and these nervures, the latter of which names 

 cannot be considered as a dimunitive of the former, but has 

 always been used and intended as a distinct term), and after 

 also citing my observations in the "Genera of Diurnal Lepidoptera," 

 hesitates to accept the premises, because he denies that a single 

 observation has ever been made that can warrant such a conclu- 



