Lawson on Aphis Avence. 271 



them. A particular account of them will be given in my Report 

 in the forthcoming volume of Transactions of our State Agricultu- 

 ral Society. And aiding these parasites in the work which they 

 have been created to perform, are several other insects, to which 

 I can only briefly allude. A lady bug or Coccinella (C 9-notata, 

 Herbst) a pretty little beetle, nearly the size and shape of a half 

 pea, of a bright yellow or red color, with nine small black spots, 

 has all season been common in our grain field, it and its larvae 

 feeding on this aphis. Another insect of the same kind, but much 

 smaller and black, with ten yellow dots on its wing covers, (J5ra- 

 chyacantha 10-pustulata, Melsheimer,) is little less common. The 

 Chrosopa, or Goldeneye flies, are also there, placing their white 

 eggs at the summit of slender threads, that their young may feed 

 on these lice. The larvae of diflferent Syrphus flies, small worms 

 shaped like leeches, may also be seen on the grain heads, reaching 

 about as an elephant does with his trunk, till an aphis is found, 

 which is thereupon immediately seized and pulled from its foothold 

 and devoured. " 



In Britain, the aphides are fed upon by earwigs. 



We have in Canada a large number of aphides, two of which 

 were very destructive last year. One of them, Aphis Brassicce^ 

 attacks cauliflowers, Brussels sprouts, cabbages, (fee, and another 

 Aphis Cerasi, is very injurious to the cherry tree, especially in 

 orchard houses and sheltered situations. These two species have 

 been fully described in the Proceedings of the Botanical Society 

 of Canada. 



ARTICLE XXYI. — On the footprints of Limulus as compared 

 with the Protichnites of the Potsdam sandstone. By J. W. 

 Dawson, LL.D., F.R.S., <fec. 



Prof. Owen in his description of the remarkable footprints from 

 the Potsdam sandstone of Beauharnois, submitted to him by Sir 

 W. E. Logan,* after referring these probably to crustaceans, re- 

 marks, "The Limuhis, which has the small anterior pair of limbs 

 near the middle line, and the next four lateral pairs of limbs bi- 

 furcate at the free extremity, the last pair of lateral limbs with 

 four lamelliform appendages, and a long and slender hard tail, 

 comes the nearest to my idea of the kind of animal which has 

 left the impressions on the Potsdam sandstone." I do not know 

 that this view of Prof. Owen has ever been subjected to the test 

 of experiment, and having on a late visit to Orchard Beach ob- 



* Journal of Geological Society of London. Vol. 8. 



