Introduction to Animal Morphology. 401 



wax. 7. Cicadids — head short, vertical ; eyes prominent ; 

 ocelli three ; antennae internal to the eyes, seven-jointed ; a 

 bursa copulatrix and two receptacula seminis ; intestine 6-10 

 times as long as body ; a drum-head-like elastic membrane 

 lies on the under side of the first abdominal ring in the male, 

 whose tension is altered by a muscle producing the charac- 

 teristic shrill TCTTtycoi'ta ; behind this drum-head is a vesicular 

 trachea. 



Sub-order 3. Heteroptera {Laireille) — anterior wings 

 hemielytrse, horny in front, membranous behind. The first 

 four families are aquatic (Hydrocores), the others are terres- 

 trial (Geocores). i. Notonectidae — back convex ; venter flat ; 

 head large ; antennae four-jointed, hidden ; ocelli none : hind 

 legs flattened, natatory, bristled along their edge ; anterior 

 tarsus one- (Corixa, Sigara) or three-jointed (Notonecta). 

 2. Nepidae, Water Scorpions — broad and flat; caput receptum ; 

 eyes large, and no ocelli ; fore feet for grasping, hinder for 

 swimming; stigmata with sieve-like opercula. In Ranatra 

 there are large, thoracic, tracheal vesicles and largely deve- 

 loped tracheae elsewhere. Nepa and Ranatra have also two 

 tracheal tubes opening at the anus. 3. Galgulidae — body 

 discoidal ; antennae four-jointed ; ocelli distinct. 4. Ploteres — 

 body small, with no neck, silky haired below ; antennae long, 

 four-jointed ; middle and hind legs long, whereby they can 

 leap on the surface of the water. Halobates inhabits the 

 Pacific Ocean. Hydrometra has a large pro-, overlapping 

 the meso-, thorax. 5. Reduviidae — tropical ; head free ; an- 

 tennae thread-like, four-join+ed ; proboscis subulate, triar- 

 throus ; prothorax with transverse constrictions. Conorhinus 

 sometimes sucks human blood. 6. Membranacei — flat, usually 

 wingless, with four-jointed antennas, three-jointed vagina, 

 and two-jointed tarsus. Cimex, the bed bug (introduced into 

 England in the sixteenth century), has no ocelli. Aradus has 

 wings. 7. Capsidae — head small, recept, trigonal ; ocelli 

 none ; eyes small ; vagina four-jointed ; tarsi unequal, three- 

 jointed ; hemielytra with an appendage in front of the 

 membranous part. 8. Corisidae — head flattened, deeply 

 recept ; ocelli two ; antennae thread-like, often highly 

 coloured ; wings membranous, often with forked veins ; 



2D 



