402 Introduction to Animal Morphology. 



mostly tropical. Anisoscelis has dilated tibiae : some have 

 remarkable forms. 



Order 3. Thysanura (Latreille} wingless, ametabolous, 

 living in damp, dark places, hair- or scale-clad, rarely with 

 compound eyes, but with two groups of 6-14 ocelli ; mouth 

 masticate rv ; Malpighian tubes few, long ; abdomen with ter- 

 minal bristles or a bifid tail. Lepisma has the typical lower 

 lip of Orthoptera ; others have no trace of a second maxilla, 

 as in Myriopods. They include two families : i. Poduridae 

 cylindrical mouth, small, with no palp ; abdomen 6-3 ringed, 

 with a fork-like tail, whereby they can spring ; hairy or scaly 

 back ; prothorax small, hidden; ocelli four (Achorutes), seven 

 (Desoria), or eight. Cyphoderus has a cup-like mesothorax. 

 Podura scales, bein^ r finely lined, are used as test objects for 

 the microscope. Smynthurus has cephalic stigmata. 2. Le- 

 l>ismi(loj fusiform, with small metallic scales and many- 

 jointed antenna: ; abdomen ten-ringed, with five end-bristles, 

 of which the middle is the largest. Machilis (Petrobius) has 

 compound ( oletia is blind. Lepisma, the scales of 



\vhich are also commonly used as microscope tests, lives in 

 sugar. 



Order 4. Thvsanoptrro. (Holiday) small, flattened, found 

 in vegetables ; head cylindrical ; mouth suctorial, directed 

 downwards and backwards ; maxillae fused with the labrum ; 

 mandibles bristle-like ; antennae 8-9 jointed ; eyes large ; 

 ocelli present ; maxillary palp 2-3 jointed ; labial two-jointed ; 

 prothorax small ; wings two pair, equally long, bristled, not 

 folded, with few veins ; rarely short or none. Tarsi two-jointed, 

 with a sucking disk and no claws ; intestine about twice as 

 long as the body; malpighian tubes four, free at the t; 

 The females of Thrips have a compressed four-valved ovi- 

 positor. Phlocothrips has a tubular last abdominal segment 

 in both se 



Orders. Euplexoptera (West-wood): Earwigs head free; 

 clypeus short ; labrum large, crescentic ; labium cleft to the 

 base of its stipites ; ocelli none ; eyes over the thread-like 

 12-40 jointed antennae; prothorax quadrangular; hemielytrae 

 much shorter than the abdomen, with no membranous area ; 

 hinder wings thin, fan-like, with radial costae, useless for 



