Symphypleona — Protura. 83 



1. Furcula wanting; body naked or hairy, never with scales; antennae four-jointed, 



often poorly-developed; claws two or one; sluggish species. (An^da, 



Neanfira) {ANURIDIDM) APHORURED^ 



Furcula present 2 



2. Furcula attached to the penultimate abdominal segment; body sometimes 



clothed with scales; antennae four- to six-jointed; claws two. (Isotoma, 

 Orchesella, Tomocerus) (PI. 16, figs. 380, 381). 



{DEGEERIIDJE) ENTOMOBRYID^ 



Furcula attached to the antepenultimate abdominal segment; body without 



scales; antennae four-jointed; claws two or one. (Podftra, Achorfites.) 



{ACHORUTIDM) PODURID.ffi 



C ORDER SYMPHYPLEONA. 



Body shortened; abdomen globose, its segments in part fused; 

 head usually vertical; ventral tube always long and well developed, 

 usually with two long, exsertile filaments; furcula well developed; 

 no post antennal organ; heart with two pairs of ostioles. 



1. Last joint of the antennae long, usually divided into false ring joints (annuli); 



upper claw unindentate. (Sminthiirus.) (PI. 16, fig. 384). 



SMINTHURIDiE 

 Last joint of antennae short, not ringed 2 



2. Last joint of antennae with whorls of hairs; the distal part of the third joint 



annulate; head vertical; filaments of ventral tube long; thorax shorter than 



the abdomen. (Papirius.) PAPIRilD.ffi 



Distal joints of antennae simple; head horizontal; filaments of ventral tube 

 represented by two rounded tubercles; thorax longer than the abdomen. 

 (Neelus, Megalothorax.) {MEGALOTHORACIDM) NEELm.^: 



CLASS MIRIENTOMATA. 



Minute, delicate, wingless, terrestrial, blind species. Body 

 bare; antennae absent, abdomen comprising eleven segments and 

 a short anal tube, the basal three segments furnished with styles; no 

 cerci; mouthparts, formed for sucking, but retracted within the 

 head. 



ORDER PROTURA. 



Slender, head pear-shaped, labrum medially narrowed to a 

 beak, mandibles long and slender; pro thorax short; legs short, 

 tarsi one-jointed. 

 (Eosentomon) (PI. 16, fig. 385) E0SENT6MID.ffi 



