168 



January i7, 1844. 



Regular Meeting — The President in the Chair. 



Dr. Storer laid on the table a specimen of Limulus Poly- 

 phemus, of large size, picked up on the beach at Nahant. 

 The dimensions are as follows, viz. : 



Greatest width, .... 



Length without tail, . 



Across abdomen, .... 



Length of carapace, . 



Distance between the eyes, 



Weight (tail wanting.) 



Dr. Storer, on behalf of Mr. S. S. Haldeman, presented 

 a paper containing descriptions, with beautiful figures, of 

 several species of Aphis, inhabiting Pennsylvania, as fol- 

 lows : 



The following species are left in the genus as originally estab- 

 lished, and they are not all characterized from mature individuals. 

 A considerable number have been described by Rafinesque, who 

 also instituted several sub-genera ; but as far as I have been able 

 to consult his papers, he has not noticed those here given. 



1 . A. quercus-monticula : brick red, varied with light yellow- 

 ish ; antennae and legs pale, annulate with black ; abdomen flat 

 above, sometimes pale green ; appendages short, two-jointed ; eyes 

 round and projecting. Varies considerably. 



2. A. rubecula : deep brick red, outer extremities of the 

 thighs and legs black ; appendages long and taper. 



3. A. castanea-vesca : body flat above, appendages obsolete ; 

 young white, legs and antennae black, two marginal and two dorsal 

 rows of large black spots ; adult nearly black, with the spots ob- 

 solete 



4. A. bicolor : light yellowish green; head, antennae, appen- 

 dages, mesothorax, legs (except the anterior femora and part of 

 the leg) blackish. 



5. A. marginipennis : light brown, covered with white down ; 

 thorax dark, abdomen large and inflated, appendages short ; ros- 

 trum and antenna) corneous, with the extremity black ; eyes prom- 



