xiii MYRIApODA 201 



and the whole process of weaving it 'and fllliiig. it with air may be 

 watched. ; 



6. Search for spiders of other kinds and for Harvestmen in 

 garden and field, and watch their ways in their natural habitat. 

 Identify them by reference to British Spiders, by E. F. Staveley 

 (1866), or The Spiders of Great Britain and Ireland, by Blackwall 

 (1864). 



7. During the summer, look out for lime leaves with nail gaUs 

 on them. Examine them at different times during the summer, and 

 try and trace the life-history of the gall-mite inhabiting them. A 

 microscope and some section-cutting wiU. be necessary. 



Examine also the various pimple-galls due to Mites, to be found 

 on the leaves of sycamore or maple, sallow willow, alder, pear, and 

 blackthorn. 



Class III. : MYRIAPODA 



The members of this little group of Arthropods breathe 

 by tracheae like insects (see p. 210), but they differ from 

 them in the form and internal structure 

 of their bodies, and also in the raany 

 pairs of appendages which specially char- 

 acterise them. They live in dark and 

 moist spots, running or wriggling over 

 the ground, or hiding in rotten wood or 

 under a stone. The body of a Myriapod pjg_ 134. _ Two seg- 

 is of much the same width throughout, mexiisoi Polydesmus. 

 and there is no marked distinction be- Ventral view to show 

 ,, . J i,j • 1 J. the attachment of the 



tween thoracic aind abdominal segments, j ^ 



each of which is covered by an exo- 

 skeleton of chitin, with, in some cases, lime deposited in it. 

 Each segment has, as a rule, one or two pairs of jointed 

 appendages attached to it. 



The class Myriapoda is conveniently divided into two 

 groups, which contain respectively the Millipedes and the 

 Centipedes. 



Millipedes (Chilogkatha) 



Millipedes have cylindrical bodies and short antennae 

 (Fig. 135,. J); they are slow -moving, inoffensive little 

 creatures, with hard scaly skins of chitin and lime forming a 

 ring round each segment of the body. 



Most of the segments, except the first three and the last, 



