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TEXT-BOOK OF ENTOMOLOGY 



association fibres between the afferent fibres from the antennae, optic ganglia, 

 and ventral system, and the efferent fibres. There is then a possibility of a 

 stimulus entering the brain and passing out as a motor impulse without going 

 into the circuit of the fibres of the mushroom bodies ; or, in other words, a 

 possibility of what may be compared to reflex action in higher animals." 



The mushroom bodies have not yet been found to be present in 

 the Synaptera, but occur in the larvae, at least of those of most 



FIG. 258. Enlarged view of the trabeculum (the dotted lines ten and oM. n pass through it) 

 and its nerves, of the mushroom body, its calices and stalk, and the origin of the optic nerve 

 X 225 diameters : atn, ascending trabecular nerve ; obt. n, oblique trabecular nerve ; ten, transverse 

 nerve ; lat. n, lateral nerve ; cent, n, central nervf. 



metamorphic insects (Lepidoptera and Hymenoptera), though not 

 yet found in the larvae of Diptera. The writer has found these bodies 

 in the nymphs of the locust (Melanoplvs spretus), but not in the em- 

 bryo just before hatching. They occur in the third larval or nymph 

 stage of this insect. It is evident that by the end of the first larval 

 stage the brain attains the development seen in the third larval 

 state of the two-banded species (C. bivittatus). 



