Wing Veins of Insects. 61 



the allotted part which they play in the economy of the animal, 

 the definite function which these organs are specially created to 

 perform ; and then he mentions a series of celebrated authors who 

 have not attempted to work out conclusions which they have left 

 to be inferred from the names which they have given to the 

 various parts in question. But in this list he singularly omits 

 the names of those great modern physiologists who have actually 

 treated upon this question, including even George Newport himself, 

 whose remarks, subsequently to be cited, it is evident that he can 

 never have read. In like manner, at the same time he completely 

 ignores the peritracheal controversy which has attracted so much 

 attention lately on the continent. The following passages, from 

 the works of Owen, Burmeister and Newport, wdl prove distinctly 

 that circulation takes place in the wings of insects through these 

 nervures, veins, or whatever else they have been termed. 



Professor Owen, in his lectures on the invertebrate animals, ob- 

 serves, " The strong and numerous nervures which sustain the 

 thin alary membranes of the Lihellula are articulated processes of 

 the external chitinous tegument. A circulation can be traced 

 through these membranes, at least in their early and softer state ; 

 air vessels are abundantly spread over the supporting frame work. 



" The wings of insects are essentially flattened vesicles sustained 

 by slender but firm hollow tubes called nervures, along which 

 branches of the tracheae and channels of the circulation are con- 

 tinued. 



" The chief merit of the re-discovery of the circulation of blood 

 in insects is due to Carus, its phenomena having been witnessed 

 in the appendages of insects by other observers, as Ehrenberg, 

 Wagner, Burmeister, Bowerbank and Tyrrell." 



Professor Burmeister (Man. of Entomology, translated, p. 96) 

 observes, that " in outward appearance the wings present them- 

 selves as flexible but dry membranes, which are traversed by 

 various horny ribs. These ribs, or more properly veins, as they 

 are in fact vessels, but incorrectly called nerves, arise all from the 

 roots of the wing." And again (p. 407), " In all perfect insects of 

 the order Dictyotoptera (^Neuroptera), namely, in the wings of just 

 disclosed Libellulce{L. dcpressa) and Ephemerce {E. lutea and mar- 

 g inatd), Carus saw a distinct motion of the blood. Hemerobius chry- 

 sops, Semhlis biUneata and aS*. viridis exhibited in their wings (and 

 the latter also in their antennae) a motion of the juices. In the 

 former Carus saw the streaming blood pass upon the anterior 

 margin tlirough the chief ribs and distribute itself upon the whole 

 margin to the apex ; it returned back through the ribs, lying 



