260 



FAMILY VI. — HYDEOPHILID2E. 



sometimes indistinct. The beetles usually occur in numbers along 

 the edges of ponds, lakes and streams and rise to the surface when 

 the water is made turbid. Five species have been taken in Indiana, 

 while another may occur. 



KEY TO INDIANA SPECIES OF PHILHYDEUS. 



a. Above paler, brownish-yellow to pale pieeous. 



l>. Pro sternum distinctly carinate; length 3.5-4.5 mm. 



503. NEBULOSUS. 



bb. Prosternum not carinate. 



c. Smaller, not over 4 mm. ; mesosternal lamina very feeble, the front 

 edge without distinct angle. 504. ochbaceus. 



cc. Larger, 4-6 mm. ; mesosternal lamina prominent, with a distinct 

 angular projection. 

 d. Thorax with a large discal pieeous space. 505. hamiltoni. 

 eld. Thorax entirely dull yellow. diffusus. 

 aa. Above black or pieeous black, the margins sometimes pale. 



e. Larger. C.5-T mm. ; transversely very convex. 506. cinctus. 



ee. Smaller, not over 5.5 mm. ; subdepressed. 507. peeplexus. 



503 (1626). Philhydeus nebulosus Say, Long's Exped., II, 1824, 277; 



ibid. I, 183. 



Oval, slightly oblong, convex. Above variable from pale to dull brown- 

 ish-yellow, shining; head and under-surface pieeous. Thorax and elytra 

 sparsely and indistinctly punctured, the usual rows of coarser punctures 

 scarcely visible. Length 3.5^.5 mm. 



Throughout the State; common. May 15-October 2i. 



504 (1630). Philhydeus ocheaceus Melsh., Proc. Phil. Acad. Nat. Sei., 

 II, 1844, 101. 



Elliptical, less convex. Above pale pieeous or dull 

 smoky brown, shining; head darker, with a pale space 

 in front of each eye ; margins of thorax and elytra paler ; 

 beneath pieeous, the tibiaa and tarsi paler. Thorax and 

 elytra distinctly and rather closely punctate, the dorsal 

 " x rows very indistinct. Length 3.5-4 mm. (Fig. 128.) 



Northern half of State ; common ; less so in the 

 southern portion. April 23-October 26. Resem- 

 Fig ,v^ 8 - bles nebulosus, but smaller: prosternum not cari- 



(Onginal.) 7 ' x 



nate and punctures of upper surface more distinct. 



505 (9315). Philhydeus hamiltoni Horn, Trans. Amer. Ent. Soc, XVII, 



1890, 249. 



Oblong-oval, moderately convex. Above piceous-yellow or dull brown- 

 ish-yellow ; head pieeous ; disk of thorax with an indefinite semicircular 

 space darker. Punctures of thorax not very close; those of elytra a little 

 coarser, the discal rows faint. Length 4.5-5.5 mm. 



Lake, Starke and Laporte counties; frequent. April 23-Sep- 



