38 MYRIAPODA CHAP. 



She leaves a small opening in the top. The size of the whole 

 nest is about that of a small nut. When she is ready to lay her 

 eggs she passes them through the hole in the top, and usually 

 lays about 60 to 100 eggs at a time. The eggs, which are very 

 snlall, are coated with a glutinous fluid which causes them to 

 adhere together. When they are all laid she closes up the 

 aperture with a piece of earth moistened with her saliva ; and 

 having thus hermetically sealed the nest, she leaves the whole to 

 its fate.. The eggs hatch in about twelve days. 



A German nakiralist, Dr. Yerhoeff, has lately found that the 

 males of some Julidae undergo certain changes in the form of the 

 legs and other organs in autumn and spring. These changes are 

 probably connected with the breeding of the animal, and remind 

 us of the changes undergone during the breeding season by salmon 

 among the fishes. 



Julus breed very readily if carefully attended to and well 

 supplied with food. If they cannot obtain the food they like 

 they will not breed so well. I found that sliced apples with 

 leaves and grass formed the best food for them. 



The process in the case of Lithohius is much harder to watch. 

 Lithohius is not so plentiful as Julus terrestris, and the animals 

 are more impatient of captivity, more shy in their habits, and do 

 not breed so readily. 



In January 1889 I was given the use of a room in the lN"ew 

 Museums at Cambridge, and was allowed to fit it up as I liked, 

 so that I was able to try the effect of different degrees of light 

 and darkness, and of different degrees of warmth. I succeeded 

 *in observing the whole process. The female Lithohius is 

 furnished with two small movable hooks at the end of the 

 under surface of the body close to the opening of the oviduct. 

 These small hooks have been observed by many naturalists, but 

 their use has, so far as I know, never been described before. 

 They play an important part in the proceedings following the 

 laying of the egg. The time of breeding in Lithohius is rather 

 later than in Julus, and begins about June and continues till 

 August. There are first of all some convulsive movements of the 

 last segments of the body, and then in about ten minutes the 

 Qgg appears at the entrance of the oviduct. The Qgg is a 

 small sphere (about the size of a number five shot), rather 

 larger than that of Julus, and is covered with a sticky slime 



