Sept. 1, 1867.] 



HARDWICKE'S SCIENCE-GOSSIP. 



211 



bis microscope, let him search diligently for the ova 

 of the above-named Acarus (Tetranychus lapidum). 

 They are of pearly whiteness, cup-shaped, with a 

 cover slightly larger than the cup itself, and marked 

 with a number of raised lines radiating from near 

 the centre to the circumference. This cover is, I 

 believe, pushed aside, when the larva makes its 

 entrance into the world. The ova are to be found 

 on the upper surface of stones, on open downs, and 

 in similar situations; the masses standing boldly 

 out, so as to be plainly conspicuous to the naked 

 eye. When placed under the microscope, they bear 

 considerable resemblance to some forms of minute 

 fungi. A friend of mine has found them in this 

 neighbourhood (Clifton), on a singular nidus, viz., 

 the paper envelope of used-up cartridges, which had 

 been fired off by Volunteers while practising. The 

 acari have taken advantage of the tiny folds and 

 sinuosities in the paper, and have filled them with 

 irregular rows of ova. The fact of the ova being- 

 found on paper shows that the acari do not confine 

 themselves (as their specific name would imply) to 

 stones. A notice of this curious acarus may be 

 found at page 22 of Science-Gossip for 1865, and 

 again at page 120 of the volume for the present 

 year, where there are also figures of the animal and 

 its ova. The central portion of the ovum in this 

 figure is not quite accurate. It should be " um- 

 bonate," not plane, much less depressed at the 

 centre. — W. W. Spicer. 



Slough of Amobiuji. — A friend, a few years 

 since, gave me the exuvia of the larva of some beetle 

 which he had found in an old book in his office, ask- 

 ing me if I could inform -him to which of the coleo- 

 ptera it belonged. This I was unable to do, and until 

 lately had no opportunity of learning anything re- 

 specting it. One day, looking into a closet in my 

 study, the receptacle of many odds and ends, I 

 found an old tray, divided into compartments, and 

 which had beeu made for some round game of cards : 

 this was so perforated by the larva of Amobium that 



Fig. 206. Scales from Larva of Amobium. 



it broke on laying hands on it. In one of the com- 

 partments, in the midst of a quantity of the dust 

 from these borings, lay some of the beetles and three 

 or four of the larva-sloughs which I instantlv re- 



cognised as the same I have alluded to. The 

 body is divided into twelve segments, covered with 

 scales of two kinds ; one, comparatively broad and 

 marked with fine striae, the others long, narrow, and 

 hair-like ; attached to the last segment is a bunch of 

 veryllongi hairs. The jaws are strong and of a 

 brown colour; antenna? short, and appearing to 

 consist of only three or four joints ; the legs ter- 

 minated with simple claws. The scales and details 

 of the head are well seen with a 5-inch objective. 

 I may observe that the ticking sound, familiarly 

 known as the death-watch, proceeded at, all hours 

 during the spring, from the above-mentioned closet, 

 leading me to think that the amobium produced 

 it.—/. B. B. 



Centring Objects. — Mr. G. Guyon describes 

 his very ingenious manner of centring objects upon 

 slides ; but I think I have a better. For a long time 

 I have been in the habit of picking out single 

 specimens of Diatoms and mounting but one on a 

 slide. Thus I can keep my cabinet in order, and in 

 time have representatives of every species. I used 

 for some time a white card having a space three 

 inches by one set out on it, and with a small black 

 spot at the centre. On this I place my slide, and 

 the spot serves as a guide to place the object. 

 Small Diatoms are readily seen against the black 

 background. I have now a card with a raised 

 edge, made of thick cardboard, around three sides 

 of it, and three ink spots, so that I can at once 

 drop the slide into its place, and mount on it one or 

 three objects, each under its own cover. I cannot 

 understand why so many persons find difficulty in 

 making Diatoms stick to the slide ; my experience 

 has been that, if they are not quite clean the dirt 

 holds them well enough, and if they are clean, that 

 they often hold so tight when dry that it is even 

 difficult to brush them off.— A. M. Edwards, Neio 

 York, U.S. 



Diatoms of British Columbia.— Mr. J. K. 

 Lord, in the appendix to his "Naturalist in Van- 

 couver Island and British Columbia," enumerates 

 119 species of diatomaceae found in gatherings made 

 by him in British Columbia, and on the shores of 

 Vancouver Island. 



Parasite of Harvest-men (Trombidium pha- 

 hiiHjii). — Among the thyme I noticed one of those 

 long-legged cousins of the spiders that are familiarly 

 called Harvest-men; it was the common Phalanguim 

 comutum. I was first induced to look at it by the 

 under parts appearing of a bright red hue, which, 

 however, was derived from the Scarlet Mite (Trom- 

 bidium phalangii), which so commonly infests the 

 insects of this genus. I counted no fewer than 

 forty-eight of the little pests, all sucking the poor 

 wretch's juices from his belly aud legs. — Gosse's 

 " Tenby r 



