366 POMONA COLLEGE JOURNAL OF ENTOMOLOGY 



the prosternum, which, together with the feet proper, extends forward beneath 

 the head. Eyes either absent or present ; when present consisting of a single 

 or of several to numerous simple ocelli, these rarely agglomerated or pseudo- 

 facetted. Antennas mostly long and thread-like or cylindrical, rarely club- 

 shaped or flattened, composed of 14 (rarely 12 or 13) or more segments. 

 The length of the antennse like that of the legs, is mostly inversely propor- 

 tionate to that of the body. The head bears one pair of mandibles and two 

 pair of maxillae, of which maxillae the second constitute a labium comparable 

 to that of insects. Stigmata always or nearly always with a closing apparatus. 

 Tracheal system presenting anastomoses excepting in Scutigera. Genital duct 

 unpaired, opening on the preanal segment. Anal segment enclosed in three 

 sclerites, one dorsal and two pleuro-ventral. 



Most chilopods are very sensitive to conditions of moisture ; and as a 

 result in regions like California, many forms burrow into the ground during 

 the dry season and are to be secured only by digging down in suitable places 

 until damp earth is reached. They abound both in inter-tropical and in tem- 

 perate regions, while fewer forms exist even in sub-artic and artic territory. 



Key to the Orders of Cliilopoda. 



a. Tracheae opening through seven unpaired spiracles arranged along the 



median dorsal line ; antennae very long and many jointed ; legs likewise 



extremely long, the tarsi composed of many segments ; agglomerated or 



falsely facetted. Order Schizotarsia. 



aa. Tracheae opening through paired spiracles situated in the pleural region 



between tergite and coxae of a variable number of the body segments ; 



antennae and legs moderate or short ; ocelli of eyes not agglomerated or 



falsely facetted. 



b. Trunk with fifteen leg-bearing segments^ among which the tergites 



of the 2nd. 4th, 9th, 11th and 13th are shortened or reduced ; young 



born with seven pairs of legs, subsequently acquiring the full num- 



l^er through several distinct steps or stages. Order .\namorpha. 



bb. Trunk with twenty-one or more leg-bearing segments among which 



the tergites of none are relatively reduced or shortened ; young 



hatched with the full number of legs. Order Epimorpha. 



Order schizot.-xrsia. 

 This order includes the single family Scutigeridre of which one genus, 

 Scutiger, is known to occur in the United .States. 



Genus Scutigera Lamarck. 

 Of this genus the following species occurs in California. i\lost of its 

 relatives are tropical or subtropical. 



Scutigera force /^s (Rafinesque.) 



This frirni is very common in the southeastern states where it has long 



been known. It is widely called the house-centipede because of its fretiuenting 



houses and outbuildings where it lives upon flies and other insects which it 



cai)tures with its long, lash-like tarsi. In luiildings kept cnntinumisly warm 



