HARDWICKE'S SCIENCE-GOSSIP. 



the insect to walk in any position, the action of the 

 two claws detaching these points as the fly moves 

 along. 



When the ravages of the parasite have sufficiently 

 weakened the fly by the destruction of its viscera, 

 &c, it becomes incapable of active movement, and, 

 remaining too long in a place, the viscid fluid continues 

 to exude, and then the fly " sticks to the wall." 



M. H. Robson. 



A RARE SPECIES OF HEMIPTERA. 



THE following species of Hemiptera being, I 

 believe, an undescribed one, the account of it 

 may not be uninteresting to your readers. 



It was discovered in some water percolating through 



Fig. 22.— Dorsal aspect of sp. of Hemiptera. 



Ventral aspect of Hemiptera. 



a crevice in an old wall, in conjunction with the 

 Oscillatoria decorticcuis. Fig. 22 will give a general 

 idea of the dorsal aspect of the insect. The rostrum 

 was rather blunt, and at the apex were two small 

 globose suckers, containing a viscid matter of great 

 reflecting power. Eyes not apparent. The head 

 was joined throughout its whole width with the 

 thorax, with the exception of a small semicircular 

 space on either side ; from these spaces sprang the 

 wing cases, which stamps it as an individual of an 

 Order of the Hemiptera. 



The sheath was closely covered with helical or 

 screw-like markings, which could only be brought 

 out distinctly with a high power, and forms a beau- 

 tiful object for the microscope. The first pair of legs 



were devoid of any transverse segmentations, the 

 most singular feature being a long horny spine half 

 the length of the leg, and curved towards the tarsus. 

 I have not observed these appendages before on any 

 insect. The foot was beset with seven or eight fine 

 hairs terminating in a claw, which was continued into 

 an unusually long and fine point. The middle legs 

 resembled the pair last described, except that the 

 long bristles were absent. The hind pair of legs were 

 placed low down the meta-thorax, and were composed 

 of five distinctly marked segments, the femur being 

 about twice as long as the remainder of the leg. The 

 tarsus gradually tapered, and ended in a single claw 

 surmounted by hairs, the long spine being absent. 

 The ventral view, fig. 23, shows the abdomen with its 

 eight segments tapering to the anal region. The 

 whole of the underside of the beetle was covered with 

 very fine hairs. 



Although I had the insect under observation for 

 some hours in an excavated slide, I did not once see 

 it use its wings or rise to the surface of the water as 

 if for the purpose of breathing. 



Its colour was a dark brown. 



The elytra were a pale yellow, the markings being 

 the same colour, but much more dense. 



They resembled the wing case of the boatfly 

 {Notonecta). 



Size of the object about j' s inch. 



John Davis. 



A GLANCE AT THE SCIENTIFIC WORLD 

 OF FIFTY YEARS AGO. 



HAVING had lately to consult the volumes of 

 the "Philosophical Magazine" for 1829-30, 

 I have been much interested by the view of contem- 

 porary science which they afford. The volumes 

 record the death of four great lights of science, two 

 of chemistry, Sir Humphry Davy, Dr. Wollaston, 

 and two of astronomy, Dr. Young and the Marquis 

 de la Place. They'contain the last papers written by 

 the two first named : that by Sir H. Davy on the 

 electricity of the torpedo ; that by Dr. Wollaston 

 on a method of rendering platina malleable. The 

 advance which knowledge has made since that date 

 is of course especially perceptible in geology. The 

 writers of papers on that science seem mostly to look 

 upon the literal accuracy of the Mosaic account of 

 the creation and the Noachian deluge as an axiomatic 

 truth to which the facts observed have to be made to 

 fit. One writer repudiates the idea of mineral veins 

 having their origin in fissures of the rock, and adopts 

 an explanation similar to that of the Cromarty quarry- 

 man, who told Hugh Miller that, when God made the 

 rocks, he made the fossils in them. Even geologists 

 so philosophical as De la Beche, Conybeare, and 

 Lonsdale, stoutly maintain that the appearances pre- 

 sented by the rocks, and the physical configuration of 



