GENUS HYPOCTHONIUS. 631 



time since that the creatures were adult, frequently 

 containing ripe eggs ; this fact is easily observable, as 

 the eggs are very large, and moreover it is quite pos- 

 sible to rear them. 



It is stated in the definition of the genus that the 

 cephalothorax is anchylosed to the abdomen, and this 

 is true, there is not any distinct joint between the two 

 as in Hoplophora ; but the result of the imperfect chiti- 

 nization and consequent flexibility of the cuticle, com- 

 bined with the comparative activity of the members of 

 this genus, is that the cephalothorax is capable of more 

 movement upon the abdomen than is usual in the 

 adults of the Oribatidce, although it is frequent amongst 

 the immature stages. 



The leading character of the genus, by which it may 

 be at once distinguished from all others at present 

 known, is the segmented abdomen of the adults ; this 

 again may be seen in some young larvae. 



The Rostrum is most commonly long and pointed 

 {H. palUdiilus, &c.) ; it may be blunter, H. hrevis. 

 The rostral hairs vary much, sometimes fine {H. rufii- 

 lus), sometimes serrated {H. hrevis), while in E. lanatus 

 they attain a remarkable development, and resemble 

 bunches of white wool in general appearance, although 

 not in actual structure. 



The Labium is usually short and broad, covering 

 less than half the mouth-opening, but it may be pro- 

 longed by paired organs answering to the ligula in 

 insects {H. palUdulus) ; this is common in other genera 

 of Oribatidm. 



The Palpi are long and usually almost cylindrical ; 

 nearly their whole length can generally be seen from 

 the dorsal aspect, as they are not concealed within the 

 mouth-cavity. They are slender in the typical species 

 (PI. XLIX, fig. 10), more robust in H. lanatus (fig. 

 17). The fifth joint is generally the longest. 



The Maxillae are generally weak, slightly chitinized, 

 and hardly dentate, they scarcely have the appearance 

 of crushing organs. 



