STATES OF INSECTS. 143 



you that some larvae moved by means of legs upon their 

 back a , but I was not then aware that any were furnished 

 with them both on the back and the belly at the same 

 time. By the kindness of Mr. Joseph Sparshall of Nor- 

 wich, a very ardent and indefatigable entomologist, I am 

 in possession of the larva of Rhagiumfasciatum, a timber- 

 feeding beetle. This animal on the ten intermediate seg- 

 ments of the underside of the body, which in the centre 

 form a fleshy protuberance, has oh it a double series of 

 rasps, as it were, consisting each of two rows of oblique 

 oblong prominences ; and on the seven intermediate dor- 

 sal segments there are also in the centre seven rasps of 

 three or four rows each, of similar prominences : so that 

 this animal at the same time can push itself along both by 

 dorsal and ventral prolegs. It is worthy of observation, 

 that a pair of these rasps is between the second and third 

 pair of true legs. 



Diptera. — The larva of a little gnat, Tipula stercora- 

 ria De Geer b (ChironomusM.eig.?), drags itself along by 

 the assistance of a single tubercle, placed on the under- 

 side of the first segment of the body, which the animal 

 has the power of lengthening or contracting c . That of 

 another beautiful Chironomus (C. plumosus), remarkable 

 for the feathered antennas of the male d , has two short 

 prolegs, or pediform but not retractile tentacula in the 

 same situation e . Others, as that of Tanypus maculatus, 



a See above, Vol. II. p. 281. b De Geer vi. 388. 



c Ibid. 389. d Reaum. v. t. \.f. 10. 



€ Ibid. 31. This larva has also a pair of pediform processes at the 

 anus, surrounded at the end with claws (t. v./. 4, 5, s s), which he 

 saw the animal use in locomotion ; but which he suspects to be re- 

 spiratory organs (Ibid. 33), which Latreille asserts they are. Gen. 

 Crust, et Ins, iv. 249. 



