HARVEST-SPIDERS 



133 



The abdomen is composed of ten segments, but these can be 

 distinguished only in the most primitive sub-order, the Cypho- 

 phthalmi: in other OpiHones not more than nine tergites are 

 apparent. A unique peculiarity of harvest-spiders lies in the fact 

 that the tergite and sternite of the same segment are not always 

 placed vertically opposite one another. The anus has been brought 

 forward ventrally so that the tergite primitively above it now lies 

 behind, and the sternite primitively below is now placed immed- 

 iately in front. Consequently most Opiliones have short and 

 rounded bodies. The majority of species have cryptic, or conceal- 

 ing coloration, being usually brown or grey, often with a central 

 dark band which serves to break up the outline of the animal's 

 shape and renders it inconspicuous against its natural background. 



Fig. 31. Examples of harvest-spider families: 1. (Suborder) Cy- 



phophthalmi, 2. Phalangodidae, 3. Gonyleptidae, 4. Trogulidae, 



5. Nemastomidae, 6. Ischyropsalidae, 7. Phalangiidae. (Drawings 



not to scale.) (After various authors.) 



