AMERICAN HYMENOPTERA. 33 



Order HYMENOPTERA, Linn. 



Characters. — Wings four; naked, membranous, the posterior pair 

 smaller than the anterior, with comparatively few veins. 



Mouth with horny jaws, and with a lower lip or tongue, sheathed by 

 the masillas. 



Tarsi generally five jointed. 



Abdomen armed with a multi valve saw ovipositor or sting in the 

 females. 



Larva apod and vermiform (or cruciform and pedate in one group.) 



Pupa incomplete and inactive. 



Section L Terchranfia, Latreille. 

 The abdomen of the females furnished with an instrument used as a 

 saw or borer for depositing the eggs. 



Sub-Section I. Pliytiphaga. 



Abdomen sessile, or soldered in its full width to the base of the 

 thorax. 



Group a. Serri/era. — TentliredinUlse. 

 Abdomen of female armed with saws. Anterior tibiae with two api- 

 cal spurs. 



Group h. Terehcllifera — Uroceridse. 

 Abdomen of female armed with a borer. Anterior tibia; with one 

 apical spur. 



Family TENTHREDINID.E, Leach. 



Antennpe. — The form and number of articulations or joints serves to 

 indicate the principal divisions of the family. 



Head. — Eyes large, in general widely separated. Ocelli three. La- 

 brum transverse or quadrate, pilose. Mandibles terminated with teeth, 

 often unequal on opposite sides. Labium with three laminae ; labial 

 palpi 4-jointed ; maxillary palpi 6-jointed. 



Wings. — The divisions of the genera and sub-genera are generally 

 indicated by the number, form and position of the areolets. Tlie mar- 

 ginal areolets are complete. 



TKANS. AMER. ENT. SOC. ( 5 ) JUNE, 1867. 



