418 INSECTA. 



through a circular opening made in their parietes by the teeth of the insect. 

 Generally speaking, however, these larvse live exposed on the leaves of the 

 trees and plants on which they feed. 



T. scrophularive, Lin. Five lines in length ; black ; antennae fulvous and 

 somewhat thickest at the extremity ; annuli of the abdomen, the second and 

 third excepted, margined posteriorly with yellow ; tibia and tarsi fulvous. It 

 resembles a wasp. 



The larva has twenty-two feet; white, with black head and points. It 

 feeds on the leaves of the scrophularise. 



There are various subgenera belonging to this tribe, such as Cimbcx, 

 Jfyfutoma, &c. 



The second tribe, that of the UROCEUATA, Lat, is distinguished from the 

 preceding one by the following characters : the mandibles are short and thick ; 

 the ligula is entire; the ovipositor of the females is somewhat salient and 

 composed of three threads, and sometimes capillary and spirally convulated in 

 the interior of the abdomen. 



This tribe is composed of the genus 



SIREX, Linnteus, 



The antennae of which are filiform or setaceous, vibratile, and formed by from ten 

 to twenty-five joints. The head is rounded and almost globular ; the labrum very 

 small ; the maxillary palpi are filiform with from two to five joints, and the 

 labials with three, the last of which is the thickest. The body is almost cylin- 

 drical. The anterior or posterior tarsi, and in several the colour of the 

 abdomen, differs according to the sex. The female deposits her eggs in old 

 trees, most commonly in pines. Her ovipositor is lodged at the base between 

 two valves, forming a groove. 



In Sirex proper, the antenna; are inserted near the front and consist of from 

 thirteen to twenty-five joints. The extremity of the last segment of the 

 abdomen is prolonged into a sort of tail or horn, and the ovipositor is salient 

 and formed of three filaments. 



These insects, which are tolerably large, more particularly inhabit the pine 

 forests of cold and mountainous countries, produce in flying a humming like 

 that of a Bombus, &c.; and in certain seasons have appeared in such numbers 

 as to strike the people with terror. The larva has six feet, and the posterior 

 extremity of the body terminates in a point. It lives in wood, where it spins 

 a cocoon, and completes its metamorphosis. 



The Tremex, Jurine, only differs from Sirex in having the antenna? shorter, 

 less slender at the end, and consisting of thirteen or fourteen joints. 



