species from Cedar Point on a board at the edge of the Black Channel. It would appear that the species is not often taken by collectors, since the type material from Sea Cliff, N. Y. is the only other recorded capture.

Representatives of the other genera in this family will very likely be reported from the State in later studies.

Section DACTYLOGNATHA

The members of this section differ from those of the preceding in that the last segment of the palpus usually forms a distinct thumb to the penultimate segment which ends in a claw. All the families thus far recorded from the United States fall in the superfamily Trombidoidea which includes the "red spiders," "harvest mites," etc.

Family Cheyletidae

This family has been placed among the Sarcoptidae as frequently as here but at present it is thot to be most nearly allied to the Trombidiidae. It is characterized by having the last segment of the stout, three- to five-jointed palpus provided with a short, movable papilla, near the inner side of the tip of which there may be large claws or pectinate setae. The penultimate segment is armed with a very large, stout claw. This appendage is possessed of a horizontal motion. The papilla is thot to be homologous to the thumb of the Trombidiidae. A striking character of typical Cheyletids is this pair of enormously developed palpi attached to a distinct beak. It is the most specialized palpal modification for seizing and holding prey of any found in the Acarina. The beak is distinctly separated from the body by a constriction but the cephalothorax and abdomen are not distinct. The long needle-like mandibles possessed by most of the forms are adapted for piercing. There are a few scale-like hairs on the body. The short, fivejointed legs end in two claws with a pecten between them. The front legs in some are developed into organs for clasping prey, while in others they appear to have a tactile function.. Movement is rather slow in all the species.

Most of the forms are minute and of little-known habits. Some are free, living upon scale insects and the eggs of various insects; many are known only from a large number of different birds where they feed upon parasitic lice and mites. Several forms, Picobia, Cheyletoides, etc., live for a time within the quills of various birds' feathers where they feed upon some of the other

mite residents found there. The predaceous forms can be considered as distinctly beneficial and several, among them Cheyletus pyriformis Banks, rank as natural factors of considerable importance in holding down the numbers of scale insects. Several records are also before me indicating the value of Cheyletus audax Banks and C. seminovorus Packard in destroying various Tyroglyphids infesting stored grain. A few genera are parasitic, Psorergates and Harpyrynchus on birds and Myobia upon rodents.

The eggs are deposited either singly or in small clusters and in some species a few silken threads are spun to hold them in place. A few cases are recorded of the female guarding the eggs for some time after laying them. Except for its six legs the larva resembles the parent quite closely. The male is the smaller of the sexes. But one species is thus far known to Ohio, altho a number are recorded from North America.

Cheyletus seminivorus Packard

Guide Study Insects, 1869, p. 665

I have but few specimens from Ohio and these were taken during late September. One was taken in loose soil along the Little Miami River near Yellow Springs, Ohio. Others were captured under loose bark lying on the ground in the woods on Mt. Logan. All were pale yellow in color and moved slowly. No feeding was observed. Altho this species is undoubtedly quite common thruout the United States, it is but infrequently recorded. Dr. Ewing in the Jour. Ec. Ent. V, 5, 1912, pp. 416-420 presents a discussion of its biology.

Family Erythracaridae

This family name replaces the older one of Anystidae. It is very poor in species but one of these is unusually common and at the same time beneficial. The most striking characters of the group are the contiguous radial arrangement of the coxae near the anterior end; the absence of processes on legs I and II; and the lack of shields on the integument. The demarkation between cephalothorax and abdomen is quite indistinct. The body is provided with many stout bristles. The eyes are simple and occur in one or two pairs. The mandibles are large, tapering to a point terminated by a curved claw, and are very powerful. The palpi are prominent, but slender and, except in the genus Anystis, have a thumb. The six-or seven-jointed legs are long, strong, and usually end in two or

three claws.

The larvae resemble the adults but are hexapod. But one representative of the family has thus far been taken in Ohio.

Anystis agilis Banks

Trans. Amer. Ent. Soc., XXI, 1894, p. 211

This species was long known as Actinidea agilis. A large number of specimens have been taken from so many localities that it can be considered as generally distributed in the State. From May to late September I have taken this mite in various habitats. Larval and nymphal forms predominate during the early season and adults are most common from early August until cold weather. I have taken a few adults in the spring which would seem to indicate that this stage may hibernate. Specimens have been taken on the ground and on plants in meadows, cultivated fields planted to various crops, and in waste lands and woodlands. I have never observed feeding. The mites are roundly triangular in shape, of a pale to bright red color, and, because of the long legs, are capable of rapid movement in an erratic manner. Adults average .9 mm long by .7 mm broad. The species occurs generally thruout the United States, southern Canada, Northern Mexico, and the Bermuda Islands. It is entirely predaceous in habit and is recorded as attacking various species of aphids, small caterpillars, saw-fly larvae, and small beetles. According to Banks "The young before transformation spins a white silken web on a leaf or in a crevice of bark and beneath it changes to the adult form."

Species in the genera Geckobia and Pterygosoma have been taken as parasites on various lizards in the old and new world.

Another family, Caeculidae, has thus far no known representatives within the State. It is similar to the preceding family but has several dorsal shields on the body, and legs I and II have spinebearing processes. Banks records several species from this country.

Three families of the Trombidoidea-the Trombidiidae, the Erythraeidae, and the Tetranychidae-have the coxae arranged in two groups and are thus at once distinguished from the other two families. All have representatives in Ohio.

Family Tetranychidae

The "brown", or "clover mites," and the more numerous "red spiders" as well as other small plant-feeding forms are included in this family. In all, the palpi show the claw and thumb arrangement but they are very minute and easily overlooked. The man

dibles have their basal joints united to form a plate, while the terminal joint is long and needle-like and is called a "stylet." With this organ the mites pierce the host tissue and withdraw the cell contents. The legs are moderately slender and bear scattered hairs. The tarsi are never swollen and terminate in one or two claws. Spinning glands are present in most species. Of the numerous genera in this family only a few are thot to be predaceous and concerning these there is considerable doubt. Banks suggests such a habit for Syncaligus and Raphignathus.

The definitely known plant feeding habits of the other genera immediately suggest the possibility of injury to crop plants. For some species of wide distribution and enormous reproductive capacity the total injury for the world amounts to an appalling figure. Five genera of the family Tetranychidae have thus far been taken in Ohio.

Banks considers the genus Syncaligus synonymous with Acheles, but I can see no reason for so considering it and shall employ the former. This genus includes minute reddish mites in which the legs are normally proportioned; the dorsum is not divided into small areas; the abdomen is not sutured to suggest segmentation; the short stout palpi show well the claw and thumb arrangement; and the supramandibular plate is wanting. Dr. Ewing has described several from the leaves of oak and apple in the West. The latter is quite injurious. But two species are known from Ohio.

Syncaligus cardinalis Ewing

Trans. Amer. Ent. Soc., XXXV, 1909, p. 403

This is a small bright red species which was taken by Dr. Ewing beneath lichens on Acer saccharum at Xenia, Ohio, September 14, 1910.

Syncaligus conspicuous Berlese

Acari Nuovi, Redia VI. Manv, 1910, p. 203

This is also a small bright red species measuring about .5 mm in length by .25 mm in width. The legs are short, making movement very slow. The only specimen taken was found September 24, 1923 in a mass of decayed walnut bark lying on the ground near Chillicothe. According to Banks the type material came from this country, but it is recorded but twice and seems to be rare.

The genus Bryobia is readily separated from the others in this family by having four prominent tubercles on the anterior margin of the cephalothorax and an unusually long pair of front legs. I have but one species from Ohio.

100

OHIO EXPERIMENT STATION: BULLETIN 386

Bryobia praetiosa Koch

Ubersicht der Arachniden system, 1837

It was long thot that the common clover mite of this country was distinct from the one occurring in Europe and until recently ours was known as B. pratensis Garman. Dr. A. C. Oudemans has compared material from both sides of the Atlantic and states that there is but one species involved. However, Dr. Ewing has described what he believes to be two distinct species from this country. One is found in Arizona and the other in Nebraska.

This mite is recorded from all parts of the State under varying conditions. The spherical, deep red eggs have been taken in large numbers from apple, plum, and maple trees, where they occur beneath the loose bark and in crevices on branches and twigs. They have also been taken on such plants as clover, both white and red, blue grass, peas, beans, etc. where the adults often feed during the summer. Eggs deposited in the fall upon trees remain virile thru the winter and hatch early in the spring. The young larvae begin at once to feed upon the nearest vegetation, which may be the tender leaves and blossoms of fruit trees. Here they may effect considerable injury and it is frequently found necessary to make some sulphur application to check their ravages. A winter or dormant application of Scalecide used at the rate of 1 to 15 parts of water will effectually destroy the eggs. A mixture of 1 gallon of commercial lime-sulphur, 2 gallons of flour paste, and 50 gallons of water is an effective spray for the mites. The paste is added after the lime-sulphur has been diluted.

The larvae do not have the fore legs greatly elongated and measure about .25 mm long by .2 mm wide. They are red in color. The nymphs resemble the adults in all but size and color, the former usually being of a greenish hue and smaller.

The adults measure about .8 mm long by .6 mm broad. The body is dark reddish brown while the legs are usually paler. Food contents in the body may vary the color to almost black. The integument is finely striated. There are at least three generations in Ohio and when the fall season is favorable there may be a fourth. A habit peculiar to the species is that of entering buildings during the fall. The exact prompting of this migration is still to be determined altho heat probably plays a major role. Nymphs and adults will swarm into houses, spend the entire winter there and in the spring pass to the outside. I have observed this on several occasions. There was no food supply in the form of green plants available yet thousands of the mites remained alive thruout