HYMENOPTERA. 451 



open a passage, or put them to death, and there tranquilly undergo their 

 ultimate metamorphosis. Such also are the habits of those which feed on 

 nymphs or chrysalides. Nearly all of them spin a silken cocoon, in which 

 they become nymphs. These cocoons are sometimes agglomerated, either 

 naked, or enveloped in a sort of tow or cotton, in an oval mass, frequently 

 found attached to the stems of plants. The symmetrical arrangement of 

 the cocoons of one species forms an alveolar body, resembling the honey- 

 comb of our domestic Bee. The silk of these cocoons is sometimes of a 

 uniform yellow or white, and sometimes mixed with black or, filaments of 

 two colours. Those of some species are suspended to a leaf or twig, by 

 means of a long thread. 

 There are various subgenera belonging to this tribe. 



In the second tribe, the GALLICOL^J, we find but a single nervure 

 in the inferior wings. The antennae are of equal thickness through- 

 out, or gradually enlarge, but without forming a club, and consist 

 of from thirteen to fifteen joints. The palpi are very long. The 

 ovipositor is convoluted spirally in the interior of the abdomen, and 

 has its posterior extremity lodged in a groove of the venter. 



The Gallicolse form the genus 



CYNIPS, Lin. 



These Insects seem to be hump-backed, having a small head and a thick 

 and elevated thorax. Their abdomen is compressed, carinated or trenchan 

 inferiorly, and truncated obliquely, or obtuse, at the extremity. That of 

 the females contains an ovipositor which seems to consist of a single, long, 

 and extremely slender or capillary thread convoluted spirally near the base 

 or towards the origin of the venter, and of which the terminal portion is 

 lodged under the extremity between two elongated valvulse; each of which 

 forms a semi-scabbard or sheath for it. The extremity of this ovipositor is 

 grooved, and has lateral teeth resembling the barbs on the head of an arrow; 

 with these the Insect widens the aperture it has effected in different 

 parts of plants for the purpose of receiving its eggs. The juices of those 

 plants are diffused in the wounded spots and form excrescences or tumours 

 called galls. The one most commonly known, or the gall-nut, Jlleppo gall, 

 is employed with a solution of the sulphate of iron to produce a black dye. 

 The form and solidity of these protuberances vary according to the 

 nature of the parts of the plants that have been wounded, such as the 

 leaves, petioles, buds, bark, roots, &c. Most of them are spherical; some 

 resemble fruits. Others are fibrous or hairy, like that called the bedeguar, 

 mousse chevelue, &c., which is observed on the wild Hose-trees. Some of 

 them resemble artichokes, others mushrooms, &c. &c. The eggs enclosed 

 in these excrescences increase in size and consistence, and finally produce 

 larvae destitute of feet, but frequently provided with mammillae in place of 





