. The Acarina or mites. A review of the group for the use of economic entomologists. Mites. dividing the egg (fig. 60) into lialves and exposing tlie pale vitelline membrane; tliis stage is the "deutovum" of ClaparMe. The newly hatched larva is circular or ovoid in outline, with three pairs of legs each tipped with two or three prominent claws. After attaching to the insect the larva becomes elongate and swollen with food. When full fed it drops off. seeks shelter in the soil or under a stone, and remains motionless for sev- eral weeks. The body swells and changes in form as the nymp
. The Acarina or mites. A review of the group for the use of economic entomologists. Mites. dividing the egg (fig. 60) into lialves and exposing tlie pale vitelline membrane; tliis stage is the "deutovum" of ClaparMe. The newly hatched larva is circular or ovoid in outline, with three pairs of legs each tipped with two or three prominent claws. After attaching to the insect the larva becomes elongate and swollen with food. When full fed it drops off. seeks shelter in the soil or under a stone, and remains motionless for sev- eral weeks. The body swells and changes in form as the nymph is developed within; this stage is called by Henking the nympho-chrysalis. "When ready the nymph issues from the cracked skin of the larva, and after feeding and growing, again resumes a state of repose; this stage preceding the adult condition is known as the teleio-chrysalis; from this comes the adult mite. The mature mite is not parasitic, but wanders about feed- ^ j' if ing on small insects, as plant lice, young caterpillars, and ^ f ? one species, T. locustarum Riley, is known to destroy a great many grasshopper eggs. A French species has been found destroying the root forms of the dreaded Phylloxera. The adult hibernates in sheltered pMces or in the soil; the eggs are laid in the spring, and there appears to be but one brood a year. Only a few forms have been bred; the larva of one of them is common on the house fiy in autumn, and a similar form occurs on mosquitoes. The old genus Tromhidium has been divided into many genera and subgenera, mostly by Berlese. The characters used do fig. 66.—Larva of Allo- not refer to the appearance of the mite and are often difficult thrombium and mouth to tabulate; the genera that may merit separation are given in parts. (Original.) the following table: 1. Xo crista metopica Tromhella. Crista metopica present 2 2. Sides of body with projections Chyzeria. Body without projections 3 3. Claws with a puhdJlus; eyes pedunculate; one
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