THE ACAEINA OR MITES. 



31 



the adult, except in 

 Erj^tliraeidsG but the 

 the family Rhyncho- 



anal openings, both quite elongate. The young resemble 

 having but six legs. This family was formerly called 

 generic name Erythraeus was first applied to mites of 

 lophidse. Ei-yihacai-us Berlese is the same as 

 Tarsotomus. There are several genera and sub- 

 genera, the more prominent of which are tabu- 

 lated below: 



1. Palpi without claw at tip, no visible 



"thumb"; body short and rounded; 



coxse all approximated Anystis. 



Palpi with a claw to last joint, not 

 counting the ' ' thumb " 2 



2. Thumb of palpus very small, indistinct; 



tarsi all simple; parasitic on reptiles . 3 

 Thumb of palpus very large, plain; tarsi 

 often long, sometimes curved, or 

 with false articulations; coxse ap- 

 proximate; body elongate; free- 

 living Tarsotomus. 



3. Coxse approximate; body broader than 



long Gekohia. 



Coxse in two groups; body elon- 

 gate Pterygosoma. 



Anystis and Tarsotomus are free and preda- 

 ceous, feeding on any small insects or acari 

 that they may come across. Their movements Fig. SQ.— Tarsotomus spinatus. (Author's 

 are excessively rapid and erratic, sometimes lUustration.) 



whirling about in a zigzag course like a particle of dust blown by the wind. In 

 Anystis the body is triangular and the palpi are four-jointed. In Tarsotomus the 



body is more elongate, and the 

 palpi five-jointed. 



Our one species of Anystis, A. 

 agilis Banks, is commonly found 

 running over the leaves of herbs 

 and shrubs in the search for prey. 

 It is red in color. I have seen it 

 fee'd onaphides, on small caterpil- 

 lars, and on the young larvae of the 

 currant sawfly. 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 of Tarsotomus (fig. 36) are 



known to occur about houses, but 



most of them live on trees. They 



are usually red in color, but some 



are marked with white spots and 



stripes. They are not very common 



in our country, only two species 



ha\TJig been described. Gehohia is 



found attached to various reptiles, 



especially lizards; three species are known from Europe. Pterygosoma is much 



more elongate tha^n Gehohia; one species, P. texana Banks (fig. 37), occurs on a lizard, 



Sceloporus floridanus, in the Southern States; others occur in Africa and Italy. 



88854°— 15 3 



<^^ 



Fig. Zl .—Pterygosoma texana: a, Beak above; &, below; 

 c, tip of mandibles; d, palpus; e, tarsus with claws. 

 (Author's illustration.) 



