144 STATES OF INSECTS. (Larva.) 
chiefly upon these organs; which afford very obvious 
marks of distinction. 
I. Larvze without legs. 
i. With a corneous head of determinate shape (co- 
leopterous and hymenopterous apods—Culicida, 
some Tipulariea, &c. amongst the Diptera). » 
ii. With a membranaceous head of indeterminate 
shape (Muscidae, Syrphide, and other Diptera). 
Il. Larvee with legs. 
i. With legs only, and with or without an anal pro- 
leg (Neuroptera, and many Coleoptera). 
1. Joints short and conical (Elater, Cerambyci- 
da, &c.). 
2. Joints long and subfiliform (Staphylinus, 
- Coccinella, Cicindela, &c.). 
ii. Prolegs only (many Tipulari@, and some subcu- 
taneous Lepidopterous larvee, &c.). 
iii. Both legs and prolegs (Lepidoptera, Serrifera, 
and some Coleoptera). 
1. Without claws (Serrifera, &c.). 
2. With claws (Lepidoptera, &c.). 
I should next say something upon the spiracles, or 
breathing-pores, or any other external apparatus for the 
purpose of respiration, in larvee; but I think it will be 
best to reserve the consideration of these for a subsequent 
letter. We will therefore conclude this detailed de- 
scription of their parts in their first state, with some 
account of their other 
iii. Appendages. The generality of larvae have no other 
external organs than those already described; but in se- 
veral of them we observe various kinds of retractile ones 
and others—protuberances—horn-like processes—rays, 
