616 KECORD OF CURRENT RESEARCHES RELATING TO 



These, almost at oncn, give oflf a number of tracheal branches, which 

 divide but little and terminate in the cavity of the last ring, in which 

 they are so numerous as almost completely to fill it. As the cardiac 

 tube opens widely into this last ring, we find a cavity full of blood and 

 containing an enormous number of trachea. The method of action is 

 as follows : when the vessel contracts, the blood is driven into the last 

 ring; here it is easily oxidized; when the posterior end dilates, the 

 blood passes in, and as the entrance is fenced by a trellis-work of 

 tiachete no blood-corpuscles can escape the influence of the oxygen. 

 Here, then, "the respiratory function is localized in the terminal 

 segment, and the dorsal vessel is an arterial heart." 



Some way behind the anterior orifice the dorsal vessel is covered 

 by large cells, for which the author proposes the name of pericardiac 

 cells ; these become greatly developed and connected with the sides of 

 the body ; they thus form the primitive pericardiac sinus. The point 

 of origin of the future lateral orifices is indicated by spots of greater 

 contractility, where the pericardiac cells are not developed. 



Development of the Blepharoceridse.* — Under the title of ' An 

 Unknown Discovery made by Fritz Miiller,' Professor F. Brauer 

 points out that the developmental history of the Dipteran group of 

 BlepJiaroceridce has hitherto remained unknown, and in consequence 

 its systematic position has been uncertain. He has discovered in an 

 elaborate unpublished work by Fritz Miiller, a fly described as new 

 under the name of Cunqnra torrentium ; this, however, he identifies 

 with the genera Paltosoma, Schiner, and Hapalothrix, Low, although 

 the new species is Brazilian and the latter genus is from Monte 

 Eosa, 



Now certain Dipteran-nymphs of remarkable structure in the 

 Vienna Museum, and coming from the Tyrol, prove to be exactly like 

 the pupae assigned by F. Miiller to Cariqnra. Their form is a half 

 oval and they are attached to stones by a flat transjiarent side. On 

 the removal of the insect from its case the venation of the wings was 

 seen to correspond exactly with that of Blepharocera fasciata West, 

 showing the secondary vein peculiar to the family. Probably the 

 larv^ of other genera resemble those of F. MuUer's species, which 

 must stand as Paltosoma ; the cephalic organs should be investigated 

 in them to decide whether the family belongs to the Culicidse or the 

 Tipulidas ; the former appears the more probable, and they much 

 resemble the Simulidae. The larvae of Paltosoma are woodlouse- 

 shaped, with deep segmental joints ; the lower side carries a series of 

 suckers and tracheal gills in the middle line. 



Tracheal System of Larval Libellulidse.f — Eeferring to Dr. 

 Palmen's work upon this subject. Dr. H. Hagen (pointing out that 

 that author has committed some errors of citation, &c.) follows 

 Lyonnet in showing that the stigmata of the larvae are readily 

 closed in case of necessity. Thus from the stigmata of a living 

 JEsc^na-larva, impaled with a pin which was heated in a flame, a 

 small bubble or bladder was seen protruded ; dead pinned specimens 



* ' Zool. Anzeig.,' ill. (1880) p. 134. t I^^id., p. 157. 



