288 Mr. T. J. Evans — Bionomiml Observations 



height the eggs are laid. For this purpose the animal lies 

 across the nest, and the eggs drop in one after another, 

 sticking together as they drop. Now the roofing-in alone 

 remains to be done. The animal is no longer able to walk 

 round the rim, the circumference of the circle being now 

 much reduced. The head end of the animal accordingly 

 walks round on the ground outside the nest and bites the soil 

 or nibbles a leaf ? while the anal region goes on with its delicate 

 work on the rim. It is at this point that the extreme con- 

 centration of the building faculty in the hinder end comes 

 most forcibly home to the observer. In this connexion it is 

 necessary to mention a structure of obvious importance to 

 the accuracy of the work, viz. the supra-anal process. This 

 process, with its six tactile hairs, is lowered into contact with 

 the rim before each new piece is placed in position. The 

 central chimney is sometimes quite short, but in others it is 

 the climax of the artistic effort, being narrow at the base and 

 broadening out above into an excellent funnel. 



This nest is not always built in one shift, but is always 

 completed once the eggs are laid. When the nest is finished 

 the female does not leave it immediately, but remains coiled 

 round it for about a week, and is often difficult to remove. 

 Oftentimes it also covers it up with bits of leaves and wisps 

 of grass, which, if removed, it will replace over and over 

 again. 



The nest of Brachydesmus resembles that of Polydesmus, 

 but is much smaller and more conical. 



The Julidcv, 



The Julids begin their breeding rather later in the year 

 than the Polydesmids. Neither in captivity nor outside have 

 I seen nest-building started before the end of May or the 

 beginning of June. Their mode of copulation is similar to 

 that of the Polydesmids ; but in their nest-building methods 

 they differ in several very striking and significant points. It 

 is true that the eggs of the Julids are all laid together in one 

 enclosure and at one time ; but the nest is a very cru le 

 structure compared with that of Polydesmus, and the building 

 instinct is of a much lower order. The most striking point of 

 contrast, however, is the fact that the Julid nest is mainly 

 built from the inside, the top only being laid on from the 

 outside. 



The female burrows into the loose soil until it comes to a 

 firm foundation, usually a stone, where it proceeds to make a 

 dome-shaped clearing, the shaping being done by the jaws. 



