140 Mr. P. A. Buxton on the 



across the front of the head of the mushroom body and 

 pass gradually into the substance of the protocerebral 

 lobes, and a few fibres pass into the bridge. Two small 

 bodies are found beneath the central bod}^, and these are 

 presumed to be the ocellary glomeruh of other authors, 

 though in the brain of Micropteryx there is no actual evi- 

 dence of their connection with the ocellary nerve. The 

 bridge is simple and straight; its ends are romided and 

 consist of Punktsubstanz, and into these pass the axons of 

 a few cells which are situated in the immediate neighbour- 

 hood ; the middle of the bridge is formed of a large number 

 of fibres which pass across the middle line. (I have under- 

 lined those characters which appear to indicate that the 

 brain of Micropteryx belongs to a simple type, so far as 

 morphological points are concerned.) 



It would doubtless be interesting to compare the simple 

 brain of this Protolepidopteron with that of other Lepido- 

 ptera or Trichoptera. This is, however, impossible, except 

 to a very slight degree, because the only work to which we 

 can refer is the classic paper which Flogel published in 1878, 

 and a few lines in Berlese's text-book. Flogel dealt with the 

 brains of a number of larvae and imagines of Lepidoptera, 

 and his fullest description is that of the brain of the imago 

 of Cossus. He devotes his attention to the mushroom body, 

 which differs from that of Micropteryx in several important 

 particulars. The head is developed as two cups on each 

 side, placed in apposition to one another. The two stems 

 which proceed downwards from these unite to form a 

 single cylindrical stem which stains deeply and lies in a 

 space. An inner root is given off, and this occupies the 

 usual position of that organ ; there is also a forward root 

 which runs up to the surface of the brain and there divides 

 in a complicated manner which is not further described; 

 no baclcM^ard root is described, but it is possible that this is 

 represented by one of the branches of the forward root. 

 This suggestion is an attempt to bring Cossus into line with 

 Micro])teryx, and it may well be correct, for we must remem- 

 ber that Flogel was hampered by the deficient methods 

 of his time, and that he was the earliest insect neurologist 

 in any true sense of the word. 



Berlese describes the brain of Sphinx very shortly. The 

 protocerebral lobes are large, the mushroom bodies of 

 moderate size; two pairs are present, which lie one in 

 front of the other : their stems do not miite. A mass of 



