304 



ARTHROrODA 



ing a pair of legs;, thus ghing these forms a certain resemblance to the Ilexapoda 

 (infra). The cheHcera' are strong and chehite, the pedipalpi are simple and are 

 used in walking, while the tirst pair of legs are tactile. Resjiiration occurs by 

 four pairs of trachex, the tirst of which opiens between the lirst and second 

 'thoracic' somites, a condition which deserves emhrvological in\"estigation. 

 The abdomen consists of nine or ten somites, and the heaci bears two ocelli. .\s 

 the name implies, the Solpugidx are nocturnal, li\ing by day in holes in the sand 

 and searching for their prey at night. In the Old World thev are reputed as 

 poisonous, but no poison glands occur. So/piii^j,'''- CalcoJcs* Dj lames* (tig. 424). 



Fig. 424. 

 Fig. 424. — PjI,j mcs formhliUlis * (after PutnaniV 

 Fig. 425. — Cjifli/fr hravaisi t^from Schmarda). 



Fig. 425. 

 chcliccne; 2, pedipalpi. 



Order V. Pseudoscorpii. 



These small flattened forms resemble the true scorpiions in the chelate 

 chelicenu and piedipalpii (tig. 425), and in the abdomen joined by its whole 

 breadth to the thora.x. Thev dilTer in the lack of postabdomen and sling. 

 They breathe by trachea;; have from two to four ocelli, and spinning glands 

 opening on the second abdominal somite. These animals, 2-3 mm. long, live 

 in moss, etc., and among tlustv books, feeding on mites and minute insects. 

 ChdiJ'cr* Obisium/'- Cliciiics.* 



Order VI. Phalangida. 



The alidomen in the harvestman, or 'daddv long legs,' is less eviilenlly 

 segmented than in the forms already mentioned, nor is it sharplv distinct from 

 the cephalolhorax. The small body bears four pairs of e.xceedinglv long legs; 

 the chelicera; are drawn out in long horny processes; the pedijialpi are tactile 

 organs as in the true spiders. The males possess a long penis, and the females 

 a long ovipositor. They have two or four ocelli and breathe by trachex. These 

 largely nocturnal animals are predaceous, feeding upon small mites. In struc- 

 ture they form in some ways an approach to the Acarina. rJialaiigium* 

 Liobunuin.'^ 



