510 TRANSACTIONS OF THE 



middle, and a subtriangular one near the tip ; pectus and post- 

 pectus not obviously granulated ; sternum acutely carinated ; 

 feet piceous ; venter with very numerous, oblique, irregular 

 lines. 



Var. a. Above dark reddish-brown, margin paler, spots yel- 

 low, distinct, piceous j feet pale rufous. 



My friend Dr. J. F. Melsheimer, in a letter written some 

 time since, observes that " the two yellowish maculae near 

 the apex of the elytra differ oftentimes in depth of coloring 

 and in size. I have several specimens that have the macula 

 of an irregular, others of an oval or elongated form, and the 

 color of all the different shades from a faint yellow to a light 

 brown. It delights in miry forest springs, where it feeds on 

 tender vegetables and minute insects. If it is caught and 

 pressed between the fingers, it will exude from the divisional 

 line of the stethidium (truncus) and abdomen, a white milky 

 substance. It moves with great activity." 



It undoubtedly approaches very closely to C. fenestratus of 

 Europe, which insect has the same fenestrate elytral spots 3 as 

 well as another insect which is described by Marsham under the 

 name of D. ohscurus. 



[Belongs to llyhius, and was afterwards described as Dytiscusi 

 biguttulus Germ. — Lec] 



3. C. AMBIGUUS. — Black; elytra dark reddish-brown; feet 

 rufous ; body somewhat acute behind ; vertex with obsolete 

 piceous spots. [97] 



Length not quite seven-twentieths of an inch. 



Body black, above with minute, depressed, irregular granules ; 

 head black, two indistinct piceous spots on the vertex and an ab- 

 breviated frontal line and puncture each side ; antenna) and palpi 

 pale rufous ; thorax black, dorsal line obsolete ; scutel black ; elytra 

 dark reddish-brown, immaculate, margin and base paler, apex 

 acute ; epipleura black ; sternum acutely carinated ; feet pale 

 rufous, posterior ones rufous. 



For this insect I am indebted to my friend Dr. J. F. Melsheimer, 

 who sent it to me as a distinct species. It approaches very closely 

 to E. erythropterus, but may be distinguished by its smaller size, 



[Vol. 11. 



