■458 Mr. Blackwall's Observations to ascertain 



From the cylindrical figure of the phial, it follows that all the 

 lines attached to its sides by their extremities, such as were ver- 

 tical alone excepted, formed with those sides chords to arcs of 

 various magnitudes. liOwering itself from one of these chords 

 to another, and applying the spinners to each in succession, the 

 spider soon connected the whole of them together by a line ; 

 then ascending again to the greatest altitude it could attain, and 

 dropping down by a thread to the bottom of the phial, over 

 which it walked to the opposite side : it there drew the thread 

 tight and made it fast, having prevented it from coming in con- 

 tact with the glass previously by raising the abdomen a little. 

 To this oblique line it united others, extending them in différent 

 directions, till by these means it established a communication 

 Avith every part of the phial. As there was some difficulty in 

 tracing these operations with the unassisted eye, lenses of the 

 magnifying powers of six and eight were employed. 



The spiders seen ascending into the atmosphere on the 1st of 

 October were of two distinct species ; but as the technical diffe- 

 rence of insects has engaged only a small share of my attention, 

 I shall leave the task of identifying them to those who are more 

 familiar than myself with this branch of entomology. The sub- 

 joined remarks on some of the characteristics of these insects, 

 which are more conveniently illustrated by the pen than the 

 pencil, may serve to facilitate this object. 



One species has four of its eight eyes much larger than the 

 other four. Two \yu\v situated in the front or fore-part of the 

 head are arranged thus *••* , the relative size of the dots being 

 nearly the same as that of the eyes. The other pair of small 

 ones is placed in the upper part of the head, and on each side of 

 it one of the remaining pair of large eyes is seated. This spider 

 has the abdomen rather depressed ; the anterior limbs, which it 

 raises in a menacing manner when any thing approaches it, are 



longer 



