THE CHILOPOD OR CENTERED, 109 



On the median line, usually a little farther back, are 

 the openings of the reproductive organs. 



Near the posterior end are the spinnerets, usually three 

 pairs of blunt protuberances, each of which, when magni- 

 fied, appears to be covered with hollow, jointed hairs. 

 Through these tubular hairs a fluid substance, secreted 

 by glands within the abdomen, is exuded ; and the fluid 

 is of such a nature that it immediately hardens on expo- 

 sure to the air. When the spider spins its web, it simply 

 exudes this fluid through the hundreds of openings ; and 

 the liquid streams, uniting and hardening, form a silken 

 cord of very many delicate strands. A good way to see 

 these strands is to allow a live spider, brought in from 

 the field, to attach its web, when it begins spinning, to 

 the middle of a glass slip, and then to examine the point 

 of attachment under the microscope. 



Development. The development of the spider cannot 

 well be traced in the time allotted to a beginning course 

 in zoology; suffice it, therefore, to say, that the young 

 spider, which hatches from the egg and molts a number 

 of times in coming to maturity, shows much resemblance 

 to the adult in both form and habits. Its palpi are pro- 

 portionately longer, more closely resembling true legs, 

 of which they are modifications. 



MYRIAPOD INSECTS. 

 THE CHILOPOD OR CENTIPED. 



Haunts and Habits. Overturn boards, logs, or stones 

 that have been lying on the ground for a long time in one 

 place, and you will find beneath them often numbers of 

 elongated, wingless insects, of a brownish color, with linear 

 bodies and numerous laterallv extended feet. Find speci- 



