Crustacea 235 



range from about 5,300 to about 1 1 ,000 feet. All these species are 

 peculiar to North America, whereas only one of our Cyclops is 

 confined to this continent. The species of Cyclops are con- 

 servative, and have spread over the world with little change. 

 Diaptomus, on the other hand, is plastic, giving rise to new species 

 in many localities, so that no species is world-wide in its dis- 

 tribution. 



MILLIPEDES (DIPLOPODA) 



The Millipedes are cylindrical or more or less flattened, with 

 seven antennal joints. The body segments mostly bear two 

 pairs of legs, whence the name Diplopoda. They move slowly, 

 and curl up when alarmed. The group is a very ancient one, 

 and is widely spread over the earth. In Mexico some of the 

 millipedes are of great size, but our Colorado forms are all relatively 

 small. The common cylindrical shiny ones belong to the genus 

 Parajulus; the P. venustus of Wood was found at Tolland and in 

 Gregory Canyon near Boulder, while P. garius of Chamberlin 

 comes from Tolland. Conotyla coloradensis of Chamberlin was 

 described from specimens taken at Salina, but in 1911 I found 

 it at Tolland. There is a very widespread species, Orthomorpha 

 gracilis of Koch, which is common in greenhouses in Boulder. 

 Mrs. Cockerell found it out of doors in Guatemala City, Guate- 

 mala. Dr. R. V. Chamberlin writes that it was first described 

 from greenhouses in Europe, its original home was probably the 

 Asiatic or East Indian region. It is now almost cosmopolitan, 

 being carried about with plants. Dr. Chamberlin found it in 

 the open at Birmingham, Alabama, and it is evidently well- 

 established in the warmer parts of North America. A North 

 African millipede, Diploiulus africanus of Brolemann, was found 

 in hothouses at Colorado Springs, while Polydesmus sontus of 

 Chamberlin was observed in a Denver greenhouse. 



CENTIPEDES (CHILOPODA) 



Soft, flattened, usually active animals, with only one pair of 

 legs to a segment. The first pair of legs is modified into poison 

 claws, the poison being secreted by special glands, and ejected 

 through a passage opening near the tip of the claw. The very 

 large and terrifying centipede, as long as one's finger, is Scolo- 



