36'2 QRISMOLOGY. 



3. UNGUIFORM MANDIBLES (Mandibula imguiformes). 



The parallel claw-shaped mandibles of many Di- 

 ptera. PLATE XX. FIG. 1, 2. c'. 



4. PROP (Ereisma). A bipartite retractile glutinous or- 



gan exerted from between the legs of the genus 

 SminthuruS) and employed by the animal to sup- 

 port itself when its legs fail it a . 



5. FECIFORK (Faci/urca). The anal fork on which 



the larva of Cassidce^ &c. carry their feces. PLATE 

 XVIII. FIG. 2. a. 



6. MASTIGIA (Mastigia). Two anal organs in the 



larvae of Cerura Vinula, exerting from their apex 

 a retractile flexible thread, with which they en- 

 deavour, by lashing their sides, to drive away the 

 Ichneumons. PLATE XIX. FIG. 2. a. 



7. SYRINGES (Syringia). Organs situated in various 



parts of larvae, from which they ejaculate a watery 

 fluid to annoy or drive away their enemies b . 



8. RUMULES (Rumula}. Teat-like fleshy protube- 



rances observable on the bodies of various larvae . 



9. AERI DUCTS (Aeriductus). Respiratory organs often 



foliaceous, with which the sides of the abdomen, 

 the tail, and sometimes the trunk of aquatic larvae 

 and pupae are often furnished. PLATE XXIX. 

 FIG. 37. 



10. PROLEGS (Propedes). Fleshy exarticulate pediform 

 often retractile organs, which assist various larvae 

 in walking and other motions, but which disap- 

 pear in the perfect insect. PLATE XVIII. FIG. 

 11, 12. b. 



De Geer vii. 38. t. iii./. 10. rr. b VOL, II. p. 248. 



c De Geer ii. 507. * xi./. 16. m. n. 



