Handbook of Medical Entomology Part 32

[Ill.u.s.tration: 154. Rhicephalus sanguineus, male. After Nuttall and Warburton.]

ee. First pair of legs inserted at one side of the mouth opening; male genital aperture usually on the anterior margin of the sternal plate. GAMASIDae.

This family contains a number of genera, some of which are found upon mammals, though the majority affect only other arthropods. One species, LaeLAPS STABULARIS, frequents the bedding in stables, and in one instance at least, has occasioned irritation and itching, in man.

bb. No distinct spiracle in the stigmal plate on each side of the body.

c. Body usually coriaceous, with few hairs, with a specialized seta arising from a pore near each posterior corner of the cephalothorax; no eyes; mouth parts and palpi very small; ventral openings of the abdomen large; tarsi without sucker. Not parasitic. ORIBATOIDEA.

cc. Body softer; without such specialized seta.

d. Aquatic species. HYDRACHNOIDEA.

dd. Not aquatic.

e. Palpi small, three segmented, adhering for some distance to the lip; ventral suckers at genital opening or near a.n.a.l opening usually present; no eyes; tarsi often end in suckers; beneath the skin on the venter are seen rod-like epimera that support the legs; body often entire. Adults frequently parasitic. SARCOPTOIDEA.

f. With tracheae; no ventral suckers; legs ending in claws; body divided into cephalothorax and abdomen; the female with a clavate hair between legs I and II. Usually not parasitic on birds and mammals. TARSONEMIDae

g. Hind legs of female ending in claw and sucker as in the other pairs. PEDICULOIDINae

To this sub-family belongs the genus PEDICULOIDES

P. ventricosus is described on page 69.

[Ill.u.s.tration: 155. Margaropus winthemi, male. After Nuttall and Warburton.]

[Ill.u.s.tration: 156. Margaropus winthemi, capitulum and scutum.

After Nuttall and Warburton.]

gg. Hind legs of the female end in long hairs. TARSONEMINae

TARSONEMUS INTECTUS Karpelles, normally found upon grain, is said to attack man in Hungary and Russia. Other species of the genus affect various plants (c.f. fig.

150, g).

ff. Without tracheae; no such clavate hair.

g. Genital suckers usually present; integument usually without fine parallel lines.

h. Legs short, without clavate hair on tarsi I and II. On insects. CANESTRINIDae.

hh. Legs longer, with a clavate hair on tarsi I and II.

Not normally parasitic except on bees. TYROGLYPHIDae

i. Dorsal integument more or less granulate; claws very weak, almost invisible; some hairs of the body plainly feathered; ventral apertures large.

GLYCIPHAGUS Her.

This genus occurs in the United States. In Europe the mites have been found feeding on all sorts of substances. They are known as sugar mites and cause the disease known as grocer's itch. G.

DOMESTICUS and G. PRUNORUM are old world species (fig. 150, d).

ii. Dorsal integument not granulate; claws distinct; no prominent feathered hairs; ventral aperture small.

j. Mandibles not chelate; elongate, and toothed below; body without long hairs; palpi enlarged at tip and provided with two divergent bristles. Species feed on decaying substances. _Histiostoma_ Kram.

jj. Mandibles chelate; palpi not enlarged at the tip, nor with two bristles.

k. No clavate hair on the base of tarsi I and II; no suture between cephalothorax and abdomen. Live on bees or in their nests. _Trichotarsus_ Can.

kk. A clavate or thickened hair at the base of tarsi I and II.

l. The bristle on the penultimate segment of the legs arises from near the middle; no suture between the cephalothorax and abdomen. The species, some of which occur in the United States, feed on dried fruit, etc.

_Carpoglyphus_ Robin.

ll. The bristle on the penultimate segment of the legs arise from near the tip; a suture between cephalothorax and abdomen.

m. Cephalothorax with four distinct and long bristles in a transverse row; tarsi I and II about twice as long as the preceding segment (fig. 150 f). TYROGLYPHUS Latr.

n. Some bristles on tarsi I and II near middle, distinctly spine-like; the sense hair about its length from the base of the segment. Several species in the United States belong to this group.

nn. No spine-like bristles near the middle of the tarsi; sense hair not its length from the base of the segment.

o. Of the terminal abdominal bristles, only two are about as long as the abdomen; leg I of the male greatly thickened and with a spine at apex of the femur below.

T. FARINae.

oo. Of the terminal abdominal bristles at least six or more are very long, nearly as long as the body.

p. Bristles of the body distinctly plumose or pectinate; tarsi very long. T.

LONGIOR.

pp. Bristles of the body not pectinate.

q. In mills, stored foods, grains, etc.

Third and fourth joints of hind legs scarcely twice as long as broad; abdominal bristles not unusually long; legs I and II of the male not unusually stout. T. AMERICa.n.u.s.

qq. With other characters and habits.

_T. lintneri_ (fig. 150 f) the mushroom mite, and several other species.

mm. Cephalothorax with but two long distinct bristles (besides the frontal pair), but sometimes a very minute intermediate pair; tarsi I and II unusually short and not twice as long as the preceding segment.

n. Tarsi with some stout spines. RHIZOGLYPHUS Clap.

The species of this genus are vegetable feeders. Several occur in the United States. R. PARASITICUS and R.

SPINITARSUS have been recorded from the old world, attacking human beings who handle affected plants.

nn. Tarsi with only fine hairs. MONIEZIELLA Berl.

The species of this genus, as far as known, are predaceous or feed on recently killed animal matter. Several species occur in the United States. M. (= HISTIOGASTER) ENTOMOPHAGA (fig. 152) from the old world has been recorded as injurious to man.

gg. Genital suckers absent; integument with fine parallel lines. Parasitic on birds and mammals.