IX. THE MICROPTERYGINA. 131 



booklets above and below all tbe divisions ; on the ventral surface there is only a single row, which 

 is situated in front of each articiilation. 



As development progresses in the pupa it becomes darker in colour, especially on 

 the wing-cases, where, in some female specimens, the future black markings of 

 the moth are quite discernible as long as two months before emergence. Other 

 specimens remain pale in colour until within a fortnight or three weeks of the appearance 

 of the imago, when the green colouring of the wings suddenly becomes visible through 

 their semi-transparent envelopes. 



When about to emerge the pupa works its way up the vertical tunnel by means 

 of the above-mentioned booklets, forces open the trap-door, and wriggles along the 

 horizontal burrow until it reaches the air, only the last three or four segments remaining 

 in the tree. Its anterior portions then break open and the moth crawls out and expands 

 its wings in the ordinary way, resting on the trunk of the tree, until they are of sufficient 

 strength and hardness for flight. 



The perfect insect appears in October and November. Although it must be common, 

 it is rarely seen ; specimens are consequently best obtained in the pupa state and reared 

 in captivity. The easiest way to find the pupa is to pass a straw into the horizontal 

 burrow, and move it about until it touches the trap-door. The collector is at once 

 apprised of this circumstance by a distinct hollow sound, produced by the straw when it 

 comes in contact with the lid, which acts like a miniature drum. If no such sound is 

 heard after moving the straw into every possible position, it may be assumed either that 

 the insect has left the burrow, or that it is inhabited by a larva only. When, however, a 

 pupa is actually discovered, a section of the tree-trunk should be cut out, extending from 

 about two inches above the horizontal burrow to about one foot below it, and the log, thus 

 obtained, taken home. Should a number of pupae be found in one tree the whole trunk 

 may then be taken, if practicable, and kept in a well-lighted room or a conservatory, until 

 the enclosed insects emerge. The specimens usually come out of the pupa at about five or 

 six o'clock in the evening, and if intended for the cabinet should be killed before dark, as 

 they very soon injure themselves when flying. 



The best time of year to obtain the pupa of this insect is during August and 

 September, as most of the specimens are then in that condition. Apart from the 

 indications above described, burrows containing larvae may often be known by the fresh 

 pellets of excrement which are present near the opening. The vacated burrows frequently 

 have the remains of the old pupa shell at the entrance, and generally look gnarled and 

 weather-worn. These indications are useful as guides to the collector before exploring 

 the burrow with a straw in the manner above described. 



This insect is much attracted by light, and in consequence sometimes enters shop- 

 windows and houses. In fact nearly all the captured specimens are so taken, the moth 

 being very rarely found in its native forests. This circumstance is no doubt due to its 

 very perfect protective colouring which, notwithstanding its large size, causes it to be 

 almost invisible, when resting on the branch of a tree. On one occasion I discovered a 

 specimen in this situation ; being obliged to leave it for a short time, I experienced the 

 utmost difficulty in finding it again, although I had taken a special note of its position. 

 This species appears to be much persecuted by insectivorous birds, as we may frequently 

 see its large green wings lying on the ground, where they are very conspicuous. 



