340 



Max. 



Lin". 



Max. I. 



Fig. 3. Oribata banksi, 

 mouth-parts. 



rostrum bears an additional pair of hairs. Underneath the 

 rostrum may he seen the mouth-parts, which consist of man- 

 dibles (Fig. 2), palpi (Fig. 3, Pa.), maxilla? 

 (Fig. 3, Max.), and the maxillary lip (Fig. 3, 

 Max. I. ). From the maxillary lip project the 

 maxilla? and the palpi. The maxilla? are 

 curved and blade-like, and are large and 

 highly developed in the genus Hoploderma. 

 The palpi consist usually of five segments, 

 and as a rule are very small; in the genera 

 Phthiracarus and Hoploderma, however, they 

 are large. On the posterior part of the 

 cephalothorax are found the following 

 organs: pseudostigmata, pseudostigmatic 

 organs, lamella?, lamellar hairs, interlamellar 

 hairs and sometimes a translamella, and often one or more 

 pairs of tectopedia, The pseudostigmata (Fig. 4, Ps.), formerly 

 supposed to be the true stig- 

 mata, are situated near the 

 abdominal margin and usually 

 close to the lateral margin of 

 the cephalothorax. They are of Fig. 4. 

 various forms, though usually 

 cylindrical or funnel shaped. From each pseuclostigma pro- 

 jects the pseudostigmatic organ (Fig. 4, Ps. org.). This may- 

 be filiform, fungiform, setiform, clavate, or subglobose, and is 

 often pectinate or dentate. The lamella? consist of either 

 blade-like chitinous projections, or of mere ridges. They 

 vary greatly in size and shape, and are situated on the 

 dorso-lateral part of the cephalothorax. Sometimes the la- 

 mella? project in a free end which may extend to the apex of the 

 rostrum or even beyond it. From the tip of the lamella? pro- 

 ject a pair of prominent bristles, termed the lamellar hairs. 

 The tectopedia, of which there may be as many as three pairs, 

 are generally blade-like, are situated on the sides of the 

 cephalothorax, and have either a tactile function or serve 

 to protect the coxa?. 



Psorg. 



Oribata setosa, pseudostigma and 

 pseudostigmatic organ. 



