550 PROTRACHEATA AND INSECTA. 



The most familiar representatives of the millepedes in European countries 

 are perhaps the Julidw. They have a large head, and a long, cylindrical body 



composed of upwards of SOsegments, which can be 

 rolled up spirally. They are either eyeless, or 

 furnished with aggregations of ocelli. They are 

 called snake-millepedes, and are very injurious 

 in fields and gardens, feeding on roots and 

 tuberg, like wireworms. Our species are of 

 small size, measuring from half an inch to 

 nearly two inches in length, and are mostly of 

 a dull bluish-black or lead colour. In tropical 

 countries, some species grow to the length of a 

 foot or more ; and they are described as creep- 

 Fig. 23.— Millepede (ffpirostrep- ing about the branches of the trees in the damp 

 tuspyrocephalus, Kooh.). African forests. Unlike the centipedes, the 



millepedes are very sluggish creatures, and 

 move very slowly, notwithstanding their numerous legs. The species figured, 

 Uliirostreptus pyrocephalus (Koch), inhabits South Africa. It is black, with 

 a bright red head, and is about four inches long. 



The Polydesmidce much resemble the Julidm in habits, but are more 

 flattened, and the three single pairs of legs are placed on the second, fourth, 

 and fifth segments, instead'of on the second, third, and fourth. They are 

 very hard, but very brittle. The British species are small ; but some of the 

 foreign ones attain to a considerable size. They are composed of about 20 

 segments. Some species belonging to this family have been met with 

 in the great caves of Moravia and Carinthia. All are blind. 



The Folyxenidce are very small, whitish millepedes, not exceeding one-third 

 of an inch in length in the largest species, and composed of only 9 or 10 seg- 

 ments. The head is well-marked, and they are provided with two clusters of 

 ocelli. They are found under fallen leaves. 



The Olomeridw are composed of from 10 to 13 segments above, but 

 each segment composed of four divisions below, an arrangement which 

 enables the animal to roll itself up like a ball. They are short and broad, 

 and much resemble wood-lice in shape, size, and appearance. 



CLASS ir.— PROTRACHEATA. 



This class includes the single family Pcripatidiv, the typical genus being Pei-i- 

 patus (Guilding). The few known species resemble caterpillars in appearance; 

 but have two rather long antennre, and soft, cylindrical bodies, indistinctly 

 divided into from 13 to 40 segments, each bearing a pair of imperfectly- 

 jointed feet, armed with two small claws. Tliey are viviparous, and are 

 found under leaves and among rotten wood. The Ijody is capable of great 

 extension and retraction. When first discovered, they were supposed to be 

 iliMusca, but were afterwards found to have more resemblance to the 

 My I iiipoda. There is a well-developed tracheal system, opening by incon- 

 spicuous stigmata placed irregularly over the body. The known species are 



