March 1, 1867.1 



HARDWICKE'S SCIENCE-GOSSIP. 



55 



CWR 



Eig. 39. Black Podtjra. 



seen on the floor, except during the winter months. 

 I can catch a black Podura occasionally by means 

 of oatmeal, but have to trust to my eyes and fingers 

 alone in the case of the speckled. Both kinds will, 

 however, eat oatmeal when kept in confinement. 

 I have had numbers of them both enclosed in roomy, 

 wooden cells, and have derived much pleasure while 

 watching their habits. The floors of the cells were 

 covered with moistened blotting-paper, in order 

 that the humid atmosphere in which the insects 

 live might be imitated. 



Fig. 40. Black Podura, front view, x 40. 



The Black Podura* is a most superb object under 

 the microscope, because the scales decompose light 

 strongly ; hence brilliant colours, especially purple, 

 play over the surface of the little creature when it 

 is well illuminated. I do not succeed well in the 

 preservation of dead specimens. One only has 

 hitherto afforded me a somewhat satisfactory slide : 

 it is mounted in the dry. If fluids are used, all the 

 scales come off directly. The application of fluid, 

 however, enables the examination of the mode of 

 attachment of the scales to be performed very 

 readily. 



On one occasion a fine colony of this species was 

 found on a rotten chip of wood, aad deposited in a 



* The colour varies much : some specimens are dull grey, 

 and others have bronze reflections. It has been suggested to 

 me that possibly the correct scientific name of this species is 

 Macrotoma nigra. 



deep cell for observation. They disliked their po- 

 sition exceedingly, and made vain attempts to get 

 away, but ultimately accommodated themselves to 

 circumstances pretty well. I noticed that they 

 often cast their skins. One was observed shortly 

 previous to, and immediately after, the operation. 

 During the process its colour became much paler, 

 almost white, and large drops of fluid adhered to it 

 in various places. In the course of a couple of 

 hours I looked again, when lo ! it had extricated 

 itself from the old coat, and was busy turning round 

 and round in a bran new one (which was many 

 shades darker than the old), as if to try how it 

 fitted* The exuvid (scales, antennae, portions of 

 the tracheae, &c.) were all attached to the cell-cover, 

 which I removed in order to identify the various 

 parts under high powers. The full size of the insect 

 is about one-eighth of an inch in length. 



This family produced, while in confinement, a 

 brood of young ones. The eggs were not noticed 

 because they were concealed under the rotten chip 

 of wood, but on the 18th June about twenty tiny 

 white Podura? were seen, apparently just born. 

 They were clothed with hairs and rudimentary 

 scales, the head was large in proportion to the body, 

 the eyes red, and the general resemblance to the 

 parents great. They seemed to feed greedily on 

 the fungoid growths which had arisen in the cell, 

 owing to the conditions existent there, and were 

 very active. Soon they betook themselves to an 

 oatmeal diet, and in course of time grew, so that on 

 the 3rd of July there was little except their size to 

 distinguish between them aud the old ones. They 

 had then acquired iridescence, doubtless by casting 

 off their skins several times, and behaved just like 

 their parents, running hither and thither, meanwhile 



* The process has been repeatedly witnessed since then. 

 The tail is the last part drawn out of the exuviae. I have 

 some now (Feb. 1), which were confined at the close of last 

 November, and they appear to be in perfect health. 



