of the SLUG WORM. 5 



of the velTel, afforded me an opportunity to obferve, that 

 when they had attained a certain depth, they, by moving 

 their body, preffedthe earth equally, on all fides, and thus 

 fmoothed the cavity, which they then lined with an adhe- 

 five fubftance, refembling Lac in colour, and of the na- 

 ture of filk ; though not fibrous. To this fubftance the 

 earth clofeiy adheres. The cell is rather of an oval form, 

 externally of a rude appearance, internally fmooth, and in 

 fome degree gloffy. 



As foon as the cell was compleated, they remained 

 contracted for fome time, till the yellow fkin was thrown 

 off and the pupa ftate fucceeded. In fixteen days after 

 their defcent, one end of the cell was broken off tranf- 

 verfely, and through the opening, thus made, the perfect 

 infect arofe. 



It was a fmall black fly, a little more than a quarter of 

 an inch in length, with four tranfparent wings. It is to 

 be noted, that this was the fir ft hatch of the year 1796, 

 which had now paffed through all its ftages. The fly is 

 reprefentedatyz^. 8. a. and magnified ztfig. 8. b. 



On the 7th of Auguft the eggs, placed in the leaves 

 by the flies of this firft hatch, began to be [ccn^ and on the 

 16th I firft faw the larvae of the fecond race. A number 

 of the fmalleft of thefe were collected, and I found that 

 they began to ceafe from feeding on the 11th of Septem- 

 ber ; a term of 26 days from their being hatched; and by 

 the 19th of the fame month there were none any where 

 to be feen. 



These are the principal obfervations I was able to 

 make that year. 



Having acquired a certain knowledge of the fly and 

 the eggs, I determined in the fpring of 1 797, to watch their 

 progrefs very carefully. Some young cherry trees, five 

 or fix feet high, afforded me good fubjects for this pur- 

 pofe. From the firft unfolding of their leaves. I examined 

 them every day. It was the 2d of June before I faw a 

 fly ; but eggs had been depofited the day before. 



On the 6th, as I was Handing by a fmall tree, a fly 

 came and refted on a leaf before me 3 and while I was look 



in g 



