SCIENTIFIC SUMMARY. 
215 
converts these larvae into pupae of similar form, but having four pairs of 
papilliform feet, and showing traces of the rostrum. After a second change 
the perfect Demodex is produced, but still without the sexual organs, which 
make their appearance subsequently. M. Megnin distinguishes three if not 
four forms of these parasites, which, however, he prefers to regard for the 
present as varieties of a single species, Demodex folliculorum. The commonest 
of these appears to be that of the dog (var. caninus ), which inhabits the hair- 
follicles of all parts of the body of that animal. A smaller variety ( cati ) 
is found almost solely in the sebaceous glands of the ear of the cat ; and a 
larger one (var. hominis ) in the follicles of the human face. M. Simon also 
met with similar parasites in the glands of the margin of the eyelids in sheep 
(var. ovis), but no other writer has ever seen them there. In the dog the pre- 
sence of these parasites, which occur in great numbers together in the hair 
follicles, produces a regular skin disease, or mange, but this does not appear 
to be transmissible to the human subject. 
Intelligence of Ants . — Sir John Lubbock has communicated to the 
Linnean Society, a fourth part of his “ Contributions on the habits of Ants, 
Bees, and Wasps,” in which he describes the results of numerous ingenious 
experiments made to test the intelligence of various species of the first- 
named group. Individuals of Lasius niger, engaged in fetching larvae out of 
a small glass cell, in which they passed over a somewhat complicated bridge, 
were at once stopped in their proceedings by the interposition of a small gap 
of only ^ inch ; they had not sufficient intelligence to drop this short distance, 
unless indeed they were deterred by prudential considerations as to the 
possibility of getting back, nor did those below adopt the apparently easy 
method of crowding upon each other to the required height to re-establish 
the broken communication. As an example of conscientious industry, Sir 
John cited the case of an individual ant, which he was in the habit of shut- 
ting up in a bottle before leaving home for the day ; the little prisoner when 
released immediately commenced work, and even a week’s imprisonment 
had no effect upon its zeal. From some experiments, it appears that ants 
when in difficulties in sight of their companions are by no means always 
assisted or relieved, and this is especially the case when the charms of a 
store of honey or other food come into competition with the promptings of 
the benevolent instincts. Individuals under the influence of chloroform 
were generally passed without notice, but sometimes even their friends 
would push them out of the way ; the general practice was to let friends lie, 
but to drop strangers over the edge of the board. Intoxicated ants appeared 
to be a puzzle to their friends, who, however, generally picked them up and 
carried them into the nest ; but strangers in the same condition were not so 
kindly used, they were thrown into the water and drowned. Sometimes 
mistakes occurred, strangers were carried into the nest, and friends thrown 
into the water ; no attempts were made to save the latter, but the strangers 
were generally detected and ignominiously dragged out of the nest again. 
From various experiments it appeared that the ants of an entire nest know 
and recognize each other 5 indeed even after a year’s absence, old companions 
are recognized and amicably received, whereas strangers are almost invari- 
ably attacked and maltreated, even when mixed with old friends. In this 
respect, however, different species show differences of character; Lasius 
