448 INSECTA. 



movable, squamous ovipositor that is serrated, pointed, and lodged between 

 two concave lamina, forming its sheath or case. 



It is by the alternate action of the teeth of this ovipositor, that the In- 

 sect makes a number of little holes in the branches, and various other parts 

 of trees and plants, in each of which it first deposits an egg 1 , and then a 

 foaming- liquid, the use of which, it is presumed, is to prevent the aperture 

 from closing 1 . The wounds made in this way become more and more con- 

 vex by the increasing- size of the egg 1 . Sometimes these excrescences 

 assume the form of a gall-nut, either ligneous or soft and pulpy, or resemble 

 a little fruit, according 1 to the nature of the parts of the plant that are affect- 

 ed by them. These tumours then form the domicil of the larva which in- 

 habit them either solitarily or in society. There they undergo their meta- 

 morphosis, and issue from them through a circular opening made in their 

 parietes by the teeth of the Insect. Generally speaking, however, these 

 larvae live exposed on the leaves of the trees and plants on which they feed. 



T. scrophularise, L. Five lines in length; black; antenna fulvous and 

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

 third excepted, margined posteriorly with yellow; tibiae 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 Scrophularia. 



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

 Hylotoma, &c. 



The second tribe, that of the UROCERATA, 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 sometimes very salient and composed of three threads, and some- 

 times capillary and spirally convoluted in the interior of the ab- 

 domen. 



This tribe is composed of the genus 



SIREX, Lin. 



The antenna are filiform or setaceous, vibratile, and formed by from ten 

 to twenty-five joints. The head is rounded and almost globular; thelabrum 

 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 

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

 the abdomen, differ according to the sex. The female deposits her eggs 

 in old trees, most commonly in Pines. Her ovipositor is lodged at 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. 



