108 DR. A. C. OUDEMANS — A SHORT SURVEY OF 



bend over the creature's head towards its genital aperture, where they seize 

 each egg as It is extruded and carry it back over the head to the dorsum. 

 Within a few days the female is thus covered with eggs, and then dies. — 

 The larvae, as soon as they hatch, climb upon low herbs, till they reach the 

 top of a leaf, to which they cling Avith their four hind legs, whilst waving 

 their fore legs in the hope of grasping a host. — The Ixodoidea are divided into 

 two families, viz., the ARGASiDiE (fig. 4) and the Ixodidje (fig. 3). The 

 former have a leathery and more or less rough skin, and the stigmata lie 

 between the third and fourth pairs of legs. As they attack men by night, 

 they are sometimes mistaken for bed-bugs (Cimicid^). The true ticks, 

 however, have a hard, smooth, shining, often brightly coloured skin, and the 

 stigmata are behind the fourth pair of legs. The females have only the fore 

 part of the dorsum shielded (fig. 4), while in the males the shield covers the 

 whole upper surface. 



From an economic point of view both Argasid^ and Ixodid^ are most 

 noxious creatures, the former being the disseminators of relapsing fever in 

 man and a fatal disease in poultry, while the latter are responsible for about 

 half-a-dozen dangerous diseases affecting various domesticated animals. 

 When the creatures are attached to the skin of a host, a drop of chloroform, 

 or ether, or benzin will soon force them to loose their hold. It is important- 

 that all stages of development should be collected, and the ticks from two 

 different hosts should neue^' be placed in one tube. 



(4) Mesostigmata, or Parasitoidea (Ensect-Mites), are generally less than 

 one millimetre in length, oval in shape, yellowish brown in colour, often w^ell 

 chitinised, more or less dorso-ventrally compressed, and more or less quick in 

 their movements. Their breathing-openings, or stigmata, lie between the 

 third and fourth pairs of legs (see fig. 5), hence the name of Mesostigmata. 

 Usually a long air-containing tube, called the peritrema, is annexed to the 

 stigma ; its signification is unknown. They prey upon creatures smallei 

 than themselves, especially other Mites, Pauropods, Spring-tails, etc. ; so that 

 in many cases they are of direct service to man by destroying other noxious 

 species, such as the mites of the genus Tetronyclius (see below, p. 113), 

 which cause damage to various cultivated plants. But there are also many 

 species which are parasitic upon birds, bats and other mammals ; e, g., the 

 species, represented in fig. 6, which sucks the blood of fowls and cage-birds. 

 Hence it comes that they live literally everywhere : among dry and decaying 

 leaves, in moss, among grass, upon or beneath the bark of trees, on the under- 

 sides of leaves, on mammals and birds, in groceries, etc. They often use 

 flying insects, such as beetles, bumble-bees, etc., as a means of transport to 

 reach better conditions, and have thus erroneously been supposed to be truly 

 parasitic upon insects. — The mandibles of the predaceous Mesostigmata end 

 in pincers, resembling the claws of a lobster, and can be protruded and 



