INVERTEBRATA, CRYPTOGAMIA, IMICROSCOPY, ETC. 245 



Moreover, it enables us to connect the phenomena of phosphorescence 

 observed in living organisms with those of organic matters in course 

 of decomposition. It is another example of a phenomenon of a 

 biological order very clearly reduced to an exclusively chemical 

 cause. 



Rhyiichopsyllus— a New Genus of Pulicida.* — This ectoparasite, 

 which has for its nearest allies Pidex, Rhynchojmon, and Ceratopsyllus, 

 was found on a Brazilian species of Molossus ; some thirty-three 

 specimens were obtained, all of which were females, and of these 

 twenty-five were taken from behind the ear ; the creature is described 

 by Professor G. Haller as being the size of a grain of rice. Although 

 the materials were so numerous, only two of the females were in the 

 completely normal condition. There are therefore two states in 

 which the female may be found, one the normal, and the other the 

 mite-like condition in which the abdomen is filled with ova. 



The various parts of the mouth organs are described, and their 

 functions explained : the well-developed proboscis pushes its way into 

 the body of the host by the aid of the saw-like movement of the 

 labrum ; the mandibles anchor themselves into the skin by the aid of 

 their backwardly directed hooks; the pincer-like maxillae are then 

 directed inwards and towards one another and so pinch up the skin 

 into a fold and produce a congestion of the blood ; the labial paljii 

 open out and the wound is increased in size. The blood is now 

 greedily taken up by the trough-like labrum and sucked into the 

 narrow oesophagus ; the oesophagus is very narrow, long, and angulated 

 in its median portion; this is succeeded by a small hemispherical vesicle 

 which has the function of a crop ; internally it is lined by a chitinous 

 layer which is not invested by epithelium, and externally there is a 

 strong muscular layer composed of a large number of circularly dis- 

 posed muscular fibres. As the chitinous layer really consists of a 

 number of rows of toothed plates, it follows that in this insect wo 

 have the comminuting apparatus of the Mandibulata connected with 

 the vesicular sucking organ of the Diptera. In the modified females 

 there is a special modification of tlie hinder portion of the tracheal 

 system ; instead of having, as has the normal female, eight pairs of 

 stigmata, it has no stigma on tlie last abdominal segment; the tracheal 

 tube ends blindly and in a large vesicle, tlie size of which is increased 

 by the diverticula which are connected with it. The function of this 

 modification is not far to seek ; the terminal segment is almost com- 

 pletely tucked into the preceding one, so that a stigma would be 

 superfluous while an air-reservoir can be easily developed from the 

 tracheal tubes anterior to it. 



Resistance of Aphides to severe Cold.t— M. J. Lichteusteiu 

 has shown that the Phylloxera of the vine (Phylloxera vastatrix) can 

 bo reproduced, either by the fecundated egg or by subterranean 

 budding colonies, on condition of having necessary nourishment and 

 heat. The latter condition appears indispensable for the agamic 



' ' Arch. Naturg.,' xlvi. (1880) p. 72. 

 t 'Coiiiptcs RemhiH,' xc. (18S()) p. 80. 



