INTERNAL ANATOMY OF INSECTS. 139 



thing similar has been observed by Reaumur with re- 

 gard to the larva of Crioceris merdigera, which forms its 

 cocoon with a kind of froth produced from the mouth a . 



iii. Famish or Gu?n. The eggs of various insects, when 

 they leave the oviduct, are covered with a kind of var- 

 nish or gum by which they adhere to the substances 

 that the young larvae are to feed upon, or are placed in 

 a proper position for their hatching in an appropriate 

 station. Several instances of this have been already 

 mentioned 5 ; I shall therefore not enlarge further upon 

 the subject. With regard to the secretion itself, little 

 has been recorded except its colour, which has been be- 

 fore noticed. Some Lepidoptera also as we learn from 

 Reaumur and Bonnet , use a varnish in the construc- 

 tion of their cocoons. 



iv. Jelly or Gluten. This secretion is particularly con- 

 spicuous in the Trichoptera and some Diptera, serving 

 as a bed or nidus for those eggs that are committed to 

 the water, upon which I have nothing to add to what 

 has been before said d . Under this head also may be 

 noticed the fluid, secreted in peculiar vesicles, that lu- 

 bricates the oviduct and the passages of the sexual or- 

 gans e . 



v. Oils. Oily substances are sometimes produced by 

 insects. The common oil-beetle (Meloe Proscarabteus) 

 when touched sends forth a drop of this kind of fluid, 

 of an orange colour, from each joint of its legs f : some- 

 thing similar I have observed in Coccinella bipunctata : 



a Reaum. iii. 230. b VOL. III. p. 79. 



c Reaum. iii. 215. Bonnet ix. 182. d VOL. III. p. 68. 



e Marcel de Serres Mem, du Mus. 1819. 133, 141. 

 f De Geer, v. 6. 



