LJNN.EAN SYSTEM. INSECTS. 163 



Tipula. Sucker without a sheath; feelers two, projecting, 



filiform. 



Musca. Sucker without a sheath, furnished with bristles. 

 Tabanus. Sucker with a single-valved sheath, furnished with 



bristles. 



Empis. Proboscis inflexed. 

 Con ops. Proboscis projecting, geniculate. 



** With a sucker, but no proboscis. 

 CEstrus. Sucker retracted within the perforated lips. 

 Asilus. Sucker straight, subulate. 

 Culex. Sheath exserted, valved, flexile, with five bristles. 



Stemmata none. 



Bombylius. Sucker very long, straight, setaceous, two-valved.. 

 Hippobosca. Sucker short, cylindrical, straight, two-valved. 



VII. APTERA. No wings. 

 * Feet six ; head distinct from the thorax. 

 Lepisma. Tail ending in setaceous bristles. 

 Podura. Tail forked, inflected, elastic. 

 Termes. Mouth with two jaws ; lip horny, four-cleft. 

 Pediculus. Mouth armed with an exsertile sting. 

 Pulex. Snout inflected, armed with a sting ; feet formed for 

 leaping. 



** Legs from eight to fourteen; head and thorax united. 



Acarus. Eyes two ; legs eight ; feelers compressed. 

 Phalangium. Eyes four ; legs eight ; feelers chelate. 

 Aranea. Eyes eight ; legs eight ; body with textorial pa. 



pilla? ; feelers clavate. 



Scorpio. Eyes eight ; legs eight ; feelers chelate. 

 Cancer. Eyes two ; legs eight, the first pair chelate. 

 Monoculus. Eyes two; legs twelve, ten of them chelate. 

 Oniscus. Eyes two ; legs fourteen. 



*** Legs numerous ; head distinct from the thorax. 

 Scolopendra. Body linear, 

 lulus. Body subcylindrical. 



(2l6.) Such are the only entomological genera founded 

 by Linnaeus. In Gmelin's edition of the Systema Na~ 

 turcB are incorporated all those subsequently defined by 

 Fabricius up to the period of its publication ; while the 

 necessity for a much larger number has been so obvious, 

 as new discoveries have been made, that even the dis- 

 M 2 



