290 GENERAL ANATOMY OR HISTOLOGY OF BLOW-FLY. 



or less triangular specks of protoplasm, which is readily stained 

 by carmine, immediately beneath the sarcolemma of the muscle 

 fibre at the point at which the nerve enters the latter (PL XVII., 

 Figs. 2 and 8). I have found it exceedingly difficult in my 

 sections to demonstrate the nerve terminals in muscle at all, 

 but in favourable sections have found a fine plexus of fibrils 

 between the muscle fibres, from which branches pass into the 

 muscle substance. In the imago the individual nerve fibrils 

 are less than I M in diameter, but in the larva they are twice as 

 large. In some sections it appears that the terminal nerve fibrils 

 are connected with the transparent isotropous substance, but on 

 this point I am by no means convinced, although the observation 

 is in accord with the statements of Engelmann and-Foetlinger. 

 The well-marked motorial end plates, described and figured 

 by Viallanes from the larva of Stratiomys and Tipula, appear 

 to me to be the connective cells which exist on the terminal 

 branches of tracheal capillaries, and I strongly suspect that the 

 so-called motor end plates described in various insects are in 

 reality the terminal cells of tracheal vessels, which are readily 

 mistaken for nerves. 



Sensory ITsrve Terminals. The cutaneous nerves either end in 

 ganglion cells or in special sensory organs. Their terminal 

 branches are much larger than those of the motor nerves, and 

 are distinctly tubular. Occasionally a distinct axis cylinder, 

 which stains deeply with logwood or carmine, appears in 

 transverse sections as a central point in the nerve cylinder. 



The terminal ganglion cells on the sensory nerves frequently 

 give off a process which enters a trichogenic cell, and either 

 passes to its nucleus (PI. XVII. , Fig. 13), or ends in a granular 

 crescent on one side of the cell. These crescents are precisely 

 similar to the menisci or tactile discs described by Ranvier in 

 the pig's snout. The terminal ganglion cells also give off pro- 

 cesses which penetrate the hypodermis and end in pore canals 

 in the cuticle. Such nerve-endings are readily demonstrated 

 in the larva. 



Some of the cutaneous nerves of the larva, instead of ending 

 in a single large ganglion corpuscle, have a group of small gan- 



