ORDERS OF INSKCTS. 



169 



Order III Collembola. 



These are Apterous insects, which atfcich tlieniselves to foreign 

 bodies by means of a ventral suctorial tube. They are commonly 

 called " Spring tails," in alhision to tlie fact that the abdomen 

 carries a long forkeil appendage, which is employed as an elastic 



Fig, 113. — Types of Aptcra. A, PetHcului ]tiiin"iiii.< ni^iill^, one of the Anoplura ; B, 

 Doeophorus liamat^vi, one of the Bird-lice ; C, t'iiiii.i>->il'"i, one of the Thysanura ; D, 

 Degeeria, one of the Poduridm ; E, Si-ale of a PmUtrid, as seen under t.lie micro- 

 scope; F, Degeeria pKrpurasceus. Ai! tlie liyures are ^Te.itly enlai-ged. (After 

 Packard and Gervais.) 



spring, and which enables the insect to etTect extensive leaps (fig. 

 113, D and F). The best-known members of the group are the Podurce, 

 which are generally found in moist dark places in gardens and in 

 similar situations. 



Ordep. IV. Thysanura. 



Tliis order comprises insects such as Lvpisma and i'ampodea (fig. 

 11.3, C), whicli are nearly related to the preceding, but are distin- 

 guished by tlie possession of a masticatory mouth, and by the fact 



