HTMENOPTERA. 447 



Almost all Hymenopterous Insects, in their perfect state, live on 

 flowers, and are usually most abundant in southern climates. Their 

 period of life, from their birth to their ultimate metamorphosis, is 

 limited to a year. 



I will divide this order into two sections. 



The first, or that of the Terecrantia, is characterized by the 

 presence of an ovipositor in the females. 



I divide this section into two great families. 



FAMILY I. 



SECURIFERA(l). 



Our first family is distinguished from the following ones by a sess- 

 ile abdomen, or the base of which is joined to the thorax throughout 

 its whole thickness, that seems to be a continuation of it, and to have 

 no separate motion. 



The females are provided with an ovipositor that is most com- 

 monly serrated, and which not only enables them to deposit their 

 eggs, but likewise to prepare a place for their reception. The 

 larvcs always have six squamous feet, and frequently others that are 

 membranous. 



This family is composed of two tribes. 



In the first, that of the Tenthredinet^, vulgarly termed Saw- 

 Jlies, we observe elongated and compressed mandibles; a trifid or 

 sort of digitated ligula; an ovipositor formed of two serrated, point- 

 ed blades, united and lodged in a groove under the anus. The 

 maxillary palpi are all composed of six joints, and the labials of 

 four; the latter are always the shortest. The wings are always di- 

 vided into numerous cells. This tribe forms the genus 



Tenthredo, Lin. 



The cylindrical abdomen of these Insects which is rounded posteriorly, 

 composed of nine annuli, and so closely joined to the thorax that the two 

 seem to be continuous; the ragg-ed appearance of their wings; the two little 

 rounded, granular, and usually coloured bodies situated behind the scutel- 

 lum, together with their heavy port, cause them to be easily recognized. 

 The abdomen of the female presents at its inferior extremity a double. 



(1) Hatchet bearers. 



