Mee 
INSECTA. 301 
The species of this genus occur only in man and some mammals, 
whose blood they suck. Their motion is sluggish. 
The louse of the human head has been investigated anatomically 
by our Swammerpam. The intestinal canal is straight, with a large 
stomach ; there are four vessels secreting urine. Each ovary con- 
sists of five tubes. The nervous system consists, besides the cere- 
bral ganglion, of three large ganglia in the thorax, so closely placed 
behind each other as to touch ; from these ganglia the nerves of the 
feet arise, and from the last ganglion arise in addition six nerves 
which are distributed through the cavity of the abdomen. 
See SwaAMMERDAM Bijbel der natuur. bl. 63—86. Tab, 1. 1.1 
Sub-genera Phthirus, Hematopinus, Pediculus Leacu. 
Sp. Pediculus humanus capitis, Pediculus cervicalis Lracu, Dr Guer Jns. 
vil. Tab. 1. fig. 6, Dumirm Consid. gen. 8.1. Ins. Pl. 53, figsey Ts 02s 
GuéRiIn Icon. Ins. Pl. 2, fig. 5. (Comp. also SWAMMERDAM, and a gigantic 
figure twenty inches long by Hooke Micrograph. Tab. 35). The larger 
species, considered by LinN&US as a variety, which lives upon the body 
and amongst the garments, differs by the less deep incisures in the side of 
the abdomen at each ring, by a thorax broader behind, and, as Guérrin hag 
remarked, by longer antenne. Pediculus humanus corporis Du GEER, 
Ins. 1.1. fig. 5, (Pediculus humanus Leracu, Pediculus vestimenti Burm.) 
As a third parasitic species of man may be added Pediculis pubis L.., 
Phthirus inguinalis Lnacu, Rept Exper. circa generationem Insectorum, Am- 
. stelodani, 1688, 12mo, Tab. 12, fig. superior, GuiRin op. cit. fig. 17, 
-Family VI. Mallophaga. Mouth supplied with mandibles 
and maxille. Tarsi biarticulate, with a single claw or with two. 
On Mammalia, and especially on Birds, different parasitic Insects 
are found, which were placed by Leyyus in the genus Pediculus, 
but which differ from it by the presence of jaws on the under 
surface of the head. Dr GeER, who discovered this character, 
justly held it to be so important and essential, that he placed these 
animals in a distinct genus, to which he gave the name of Ricinus 
ee ee eee 
1 LEEUWENHOECK investigated the male louse (which is rarer and was unknown 
to SWAMMERDAM, op. cit. bl. 83); he found two testes on each side of the body. 
This and other remarkable peculiarities in Pediculus hum. corporis are found in 
LEEUWENHOECK, sesde Vervoly. der Brieven. Delft, 1697, 98ste Missive, pp. 187—217, 
See also Vierde Vervoly. der Brieven 1694, 77ste Missive, pp. 587—s91, where the 
head is described and figured. The horny sheath of the 
penis L. described as a sting 
at the posterior part of the body, 
