6 ON THE CATERPILLARS OF SAW-FLIES. 



*** Forming an irregular double cocoon ; each 

 being vitreous and hyaline (Pristiphora). 



**** Forming a regular simple cocoon (Ne- 

 matus, Croesus, Tenthredo rustica, &c). 

 2. Resting on the upper side of the leaves, and 

 forming regular shaped simple cocoons. 



* Larva eruciform (Tenthredo De Geerii). 



** Larva onisciform (an unknown species ob- 

 served by Dahlbom). 



*** Larva limaciform {Tenthredo atra, cerasi 

 auctorum, but not of Linnaeus). 



b. Larvae feeding on the leaflets of pines,- and forming 



a regular simple cocoon (Nematus abietinus 

 and Leacltii). 



c. Larvae living within the galls of plants (Nematus 



inter cus, &c.) 



d. Larvae living within the fruit of the apple (Ten- 



thredo testudinea). 



e. Larvae living between the two surfaces of leaves 



(Fenusa pumilaJ) 



C. Larvae with 18 legs (6 pectoral, 10 ventral and 2 



anal) ; forming a regular double cocoon ; the outer 

 one elastic and reticulated (Hylotoma enodis, 

 Rosarum). 



D. Larvae with 6 legs (6 pectoral, no ventral feet). 



1. Social; feeding within a common web (Lyda 



sylvaticQ, &c.) 



2. Solitary ; residing within a moveable case 



formed of leaves (Lyda inanita). 



3. Solitary ; residing within the stems of cereal 



plants (Cephus). 



Taylor Institute, Oxford, 

 November 17 th, 1857. 



