NATURAL SCIENCES OF PHILADELPHIA. 521 



On report of the Committee, the paper read Nov. 4th, entitled, " Ou 

 the Pedipalpes of North America, by Horatio C. Wood, M. D.," was 

 ordered to be published in the Journal ; and, on report of the respec- 

 tive Committees, the following papers were ordered to be published in 

 the Proceedings : 



>- 



Synopsis of the Species of COLYMBETES inhabiting America, north of 



Mexico. 



BY JOHN L. LE CONTE, M. D. 



The number of known species of Colymbetes, with the elytra transversely 

 striate (Cymatopterus Esch.) has been so increased within a few years that a 

 synoptic table, expressing the differences between them, is now desirable ; 

 for the purpose of avoiding the necessity of reference to scattered descriptions, 

 I have completed the table by adding the characters of the species belonging 

 to the other divisions of the genus. The measurements are in decimals of an inch. 



A. Elytra reticulate ; claws of hind tarsi not very unequal in size (except 



in sp. 8). 

 a. Body convex, very finely reticulated ; anterior and middle tarsi of male 

 very feebly dilated : Ilybius Er. 



Base of thorax broadly rounded. 



55. Black, slightly bronzed, oval, not dilated at the middle, less obtuse 

 behind ; elytra with the usual pale spots ; outer hind claw two-thirds as long 

 as the inner one. Middle States . . . . 1. lingular is Lee. 



40 -45. Black, slightly bronzed, oval, very slightly dilated at the middle, 

 less obtuse behind ; elytra with the usual pale spots ; outer hind claw three- 

 fourths as long as the inner one. Middle, Southern and Western States, and 

 Canada. Dytiscus big. Germ. ; Colymbetes fenestrates || Say ; var. II. pieuriticus 

 Lee. . . . . . . . . . 2. biguttulus Lee. 



45. Black, slightly bronzed, oval, not dilated at the middle, scarcely less 

 obtuse behind ; elytra with the usual pale spots ; the usual confused lines of 

 punctures more distinct than in the two preceding species ; outer hind claw 

 three-fourths as long as the inner one. Oregon and Russian America. 



3. quadrimaculatus AuM. 



46. Var. ? Dark-bronzed color, a little more convex than No. 3, but with the 

 lines of punctures on the elytra equally distinct ; the anterior spot is longer 

 than in No. 3. Methy ; Robert Kennicott. 



42. Brownish-black, slightly bronzed, oval, slightly dilated at the middle, 

 not less obtuse behind ; thorax with the sides nearly straight ; elytra with 

 the anterior pale spot very small, the hind one wanting ; lines of punctures 

 visible only behind the middle. North Red River. 4. fraterculus Lee. 



37 "41. Black, slightly bronzed, oval, elongate, not dilated at the middle, 

 somewhat less obtuse behind ; elytra with the usual pale spots, the hind one 

 quite large ; lines of punctures visible only behind the middle. Nebraska. 

 Ilybius laramcBus Lee. . . . . . . 5. laramseus Lee. 



36. Black, slightly bronzed, elongate oval, not dilated at the middle, less 

 obtuse behind ; elytra with the usual pale spots not visible ; confused lines 

 of punctures quite distinct to the base. . . . 6. picipes Kirby. 



36. Black, slightly bronzed, elongate oval, not dilated at the middle, not 

 less obtuse behind ; elytra with the pale spots very distinct ; confused lines of 

 punctures visible to the base ; surface less convex and more finely reticulated 

 than in C. picipes 7. ignarus Lee. 



Base of thorax bisinuate, hind angles prolonged, acute. 

 40. Elongate oval, less convex than usual, black, scarcely bronzed ; series 

 1862.] 



