Fig. 218.—Alimentary canal of Docophorus fuscicollis. (After Giebel.) a, Oesophagus; b, paunch; a′, posterior division of oesophagus; c, chylific ventricle or stomach; d, Malpighian tubes; e, small intestine; f, glandular girdle; g, rectum.
The eggs of some Mallophaga have been figured by Melnikow;[[273]] they possess at one extremity a cover with a multiple micropyle-apparatus, and at the opposite pole are provided with seta-like appendages. They are very like the eggs of the true lice, and are said in some cases to be suspended by threads to the hairs or feathers after the fashion of the eggs of Pediculi.
Little is known as to the development; the young are extremely like the adult, and are thought to moult frequently; the duration of life is quite unknown.
It has been stated by some writers that the mouth is truly of the sucking kind, and that the Mallophaga feed on the blood of their hosts. This is, however, erroneous; they eat the delicate portions of the feathers of birds, and of mammals perhaps the young hair. Their fertility is but small, and it is believed that in a state of nature they are very rarely an annoyance to their hosts. The majority of the known species live on birds; the forms that frequent mammals are less varied and have been less studied; most of them have only one claw to the feet (Fig. 220), while the greater portion of the avicolous species have two claws.
Fig. 219.—Lipeurus ternatus, male; inhabits Sarcorhamphus papa. (After Giebel.)
Fig. 220.—Trichodectes latus, male; inhabits the dog, Canis familiaris.
Most of the forms have the anterior legs small, and they are usually drawn towards the mouth, owing, it is believed, to their being used after the manner of hands to bring the food to the mouth; hence in some of our figures (219, 220) the body looks as if it had only four legs.