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nately, the temperature was raised too high, and all that lot of larvæ perished,—in fact, they were cooked.

Another cell was filled and covered with thin glass. This was decidedly better, inasmuch as in a week's time one flea had so far outgrown his companions that he spun a cocoon, and entered into a state of repose preparatory to his final change, and I had great hopes; but this change never took place, for one of his juniors, supported by a hungry friend, got inside the cocoon and gobbled up my poor protégé. I had the satisfaction, after an interval of two days, of seeing the two cannibals wriggling out of the aperture by which they had effected an entrance, while nothing remained of the former occupier, not even the skin.

Warned by this circumstance, precautions were taken to separate from the rest some half-dozen larvæ, which a few days afterwards were desirous of seeking a place of rest, and had changed considerably in colour through ceasing to eat.

The weather now became colder, and it appeared to affect the subjects of the experiment to some extent. Two of them settled down in different parts of the cell in which I had confined them, and without spinning any cocoon, prepared to undergo their metamorphosis into the imago state. Twelve days afterwards, they were noticed to have altered in appearance to something approaching the shape of the perfect flea, the resemblance becoming closer each day afterwards. The legs were formed, but soft apparently, and much distended by the contained fluids; the general colour was white, and the skin semi-transparent,—very like the colour of shrimps before boiling.

Alas! my scientific hatching did not end satisfactorily. My baby fleas proved abortive, and soon shrivelled up. The cause I have not ascertained for certain, but think I am not far out in attributing it to want of moisture, and, perhaps, want of air and food. I have not had an opportunity of completing the experiment, but hope to do so at a future time.

The place in the office where I kept my pets, was regarded with great suspicion by my companions; and I was to be held responsible, should fleas become numerous there at any future time.

This, however, involved a question which has not yet been decided, namely, whether the cat-flea will fulfil all the conditions, and rejoice in the comfort, notwithstanding its dangers, which is the lot of the bed-flea. My own impression is decidedly in the affirmative.

The cat-flea is to be distinguished from the human tormentor, by the array of spinous processes it possesses at the front of the head and back of the neck, somewhat like a collar, while the bed-flea is destitute of them. The squirrel-flea has a similar series of spines at the back of the neck, but none in the front of the head. This kind is also to be found on rats, the writer having once caught a specimen on one.

I have never seen the larva of the bed-flea. It is said to inhabit dusty corners of rooms and carpets; very likely the cat-flea larva often does the same, particularly in houses where puss is allowed to roam at will.

I lately found that oftentimes mice are infested with fleas, and procured some for my cabinet. It is remarkable in this species, that either there are no eyes or they are very obscure. I cannot find them. The figure given of the head of the bat-flea in the Micrographic Dictionary resembles the head of the flea in question.

The subject of this paper is well worth experimenting upon, and cannot fail to supply interest. The expression of all the friends who saw in my microscope the active and, apparently, ferocious worms now described, was that of surprise and wonder.

As many of our readers are, at this time of the year, amusing themselves with Pike-fishing, and as some of them are obliged to confine their attention to one stream, it may not be out of place in the pages of Science Gossip to suggest to them the use of the fly as the new sensation. All fishers have remarked that the fish in any stream soon cease to take a particular kind of artificial bait if worked too long at once. For this reason a change is extremely desirable. Mr. Pennell, in his "Book of the Pike,"^[1] has figured a fly for Pike-fishing which might be tried with advantage in some localities where it is at present unknown. We quote his own words:—

"The fly, although it has always held a recognised place amongst pike-baits, is practically very little either known or used, and the small experience I have had of it leads me to class it rather as a 'fancy bait,' which may perhaps be occasionally employed as an agreeable variety, than as a rival to the more solid and time-honoured modes of trolling. Mr. Stoddart seems to be much of the same opinion. The Pike-fly is also used in the Norfolk Broads, where, according to a recent writer in the Field newspaper, the experience to a recent writer in the Field newspaper, the experience of trollers is precisely contrary to that of Mr. Stoddart, as it is found that large-sized Pike will frequently take it freely, when nothing over 6 lbs. can be tempted with the natural bait."