ACARINA 453 



FAMILY 11. HALACABIDAE.* 



Salt-water mites. Body rather elongate, usually with a suture 

 between the 2 pairs of legs ; rostrum often large ; 3 eyes usually present ; 

 no tracheae; no swimming hairs on legs: about 10 genera and 70 species 

 known; the animals are found crawling slowly over algae in the sea, 

 being vegetal feeders; the young feed on the eggs of copepods and are 

 attached to various animals; 1 fresh- water species. 



HALACARUS Gosse (Thalassarachna Packard). Pedipalps 4-jointed, 

 long, free, and distant from each other; body convex and rather elon- 

 gate; first leg but little thicker than the second: about 41 species, 1 in 

 fresh water. 



H. verrilli (Packard). Body ovoid with a transverse suture, just 

 back of which is a pair of black eyes ; color dark, rostrum conical ; man- 

 dibles slender and almost as long as the pedipalps; length 

 1.75 mm.: on hydroids off the coast of Maine. 



FAMILY 12. BDELLIDAE. 



Snout mites (Fig. 712). Body elongate, with a trans- 

 verse suture between the second and third pairs of legs; 

 mandibles very long and large; pedipalps long and slen- 

 der ; spiracles at the base of the rostrum : about 13 Amer- 

 ican species, which are active predacious animals living 

 in moss, rotten wood, and similar places, and can move 

 backwards as well as forwards. 



BDELLA Latreille. Palps used like antennae and Fig- 712 

 elbowed, the last joint bearing 2 or more long bristles; A (Banks." 6 

 mandibles chelate: about 10 American species. 



B. marina Packard. Body red in color and 2 mm. long; last joint of 

 pedipalp not widened at tip, hairs at end not as long as the joint ; many 

 bristles on body: along Atlantic seaboard. 



B. cardinalis Banks. Body red in color and 1.2 mm. long; last joint 

 of pedipalp widened at tip, and with hair at end much longer than joint ; 

 body with about 20 bristles: in moss and on the ground. 



FAMILY 13. TROMBIDIIDAE. 



Harvest mites. Body globular or elongate, red in color, and hairy, 

 usually with a transverse suture between the second and third legs; 

 mandibles chelate; eyes often stalked (Fig. 713) ; legs end with 2 claws; 

 pedipalps 5-jointed; spiracles at the base of the mandibles; the larvae 



* See "Hydrachnidae und Halacaridae," by R. Pierslg and H. Lohrnann, Das 

 Tierreich, 1901. 



