104 



REPOET 108^ U. S. DEPARTMEXT OF AGRICULTURE. 



the stigmata are on the underside of the mandibles. He also found Ihdng unliatched 

 eggs within the body of the dead mite. Similar cases are kno\rn in the Oribatidae. 



Superfamily SARCOPTOmEA. 



Family TARSONEMID^. 



This is a small family, but of much biological and economical interest. They are 

 soft-bodied mites and in some ways resemble the TjToglj'phidae, but the females 



differ fi-om them, as well as from all other 

 Acarians, in having between legs I and II 

 a prominent clavate organ of uncertain use. 

 The mouth parts (fig. 213) are formed for 

 sucking, and the mandibles are very slen- 

 der and needle-like. The palpi are mi- 

 nute and barely Aisible. There are tracheae 

 wliich open on the ventral surface near 

 the base of the rostrum. The legs are short 

 and composed of five or six joints; the an- 

 terior tarsi terminate in one claw, the others 

 usually have two claws and often a sucker. 

 The posterior pairs of legs are quite remote 

 from the anterior pairs; in the males of Tar- 

 sonemus they are almost at the tip of the 

 body. In some species the abdomen shows 

 traces of segmentation by the presence of a 

 few transverse lines on the dorsum. The 

 anal opening is at the end of the body. 



(Au- 



FiG. 213. — Beak and claw of Fcdiculuidcs. 

 thor's illustration.) 



The genital opening in Tarsonemus is a small, elongate aj^erture near the liind coxae. 

 The body and legs are proAdded -^ith a few simple hairs. In several genera of the 

 family, notably in Tarsonemus, there is a marked difference in the structure of the 



Fig. 214. — Pcdiculoidcs vcnlricostis: Fe- 

 male. (Author's illustration.) 



Fig. 2l'i. — Pcdiculoidcs vcTUricosus: 

 Male. (Author's illustration.) 



sexes. In the male Tarsonemus the body is mucli shorter than in the female, and the 

 hind legs are thick and heavy and end in a very large claw. In tlie female the hind 

 legs are very slender and delicate, and terminate in two long hairs, one of them often 

 as long as the entire leg. In the mature female of Pcdiculoidcs (fig. 21G) the abdomen 



