50 Dr. James Macbride un t/ic Pozccr of 



The falling of the insect as soon as it enters the tube is wholly 

 attributable to the downward or inverted position of the hairs of 

 the internal surface of the leaf. At the bottom of a tube, split 

 open, the hairs are plainly discernible pointing downwards; and 

 as the eye ranges upwards they become gradually shorter and at- 

 tenuated, till at, or just below, the surface covered with the bait, 

 they are no longer perceptible to the naked eye, nor to the most 

 delicate touch. It is here that the fly cannot take a hold suffi- 

 ciently strong to support itself, but falls. The inability of insects 

 to crawl up against the points of the hairs I have often tested in 

 the most satisfactory manner. Spiders descend into the tubes, to 

 prey (I suppose) on the entrapped insects, and ascend with impu- 

 nity ; but this is performed, as 1 have witnessed, by the assistance 

 of their threads. Also a small species of Phalccna* appears to take 

 shelter in these tubes during the day, and is enabled to ascend ; 

 but by what contrivance I am at a loss to conjecture, unless it 

 be by some peculiarity of structure in its feet. 



In the putrid masses of insects thus collected, are always to be 

 seen one or more maggots in a very active state. To account 

 for their presence, and to ascertain the insect to Avhich they be- 

 longed, I was long unable. The mystery was however unveiled 

 in the following manner : While watching attentively some tall 

 lubes of the S.Jiava growing in their natural situations, in order 

 to discover whether other insects as well as flies were attracted by 

 the bait above described, a large fly caught my attention : it 

 passed rapidly from one tube to another, delaying scarcely a mo- 

 ment at the faux of each, until it found, as it should seem, one 



* This PhalcBna, which is about half an inch in length, may be described by saying it 

 is divided transversely into three equal parts ; the first division including the head is 

 black ; the second dirty white, or yellow ; the third is like the first : Larva a greenish geo- 

 meira.. 



suitable 



