260 FAMILY VI. HYDEOPHILID.E. 



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 Ijeen taken in Indiana, 

 while another may occur. 



KEY TO INDIAKA SPECIES OF PHILHYDRl'S. 



0. Above paler, brownish-yellow to i)ale piceous. 



h. Prostemum distinctly carinate ; lengrth 3.5-4.5 mm. 



503. XEiiiLosrs. 

 /*;*. Prosternum not carinate. 



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



edge without distinct angle. 504. ochracels. 



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



angular pro.iection. 



(/. Thorax with a large discal pieeous space. oii'i. iiamiltom. 



(?(?. Thorax entirely dull yellow. diefisis. 



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



c. Larger. r>.."i-7 mm.; transversely very convex. 506. cinctus. 



ec. t^nlllller. not over 5.5 mm. ; subdepressed. 507. PEKPtExus. 



503 (Kliili). PHiLHYDKrs NEBT-'LOsrs Say. Long's Exped., II, 1S24, 277: 



ibid. I, 1S3. 

 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 usiial rows of coarser punctures 

 scarcely visible. Length 3.5—1.5 mm. 



Throughout the State; common. ^lay l.l-Oetober 2i. 



504 (1630). Philhydecs ochbaceis ilelsh., Proc. Phil. Aead. Nat. Sii., 



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 tibia- and tarsi paler. Thorax and 

 elytra distinctly and rather closely punctate, the dorsal 

 rows very indistinct. Length :!.5— 1 mm. (Fig. 128.) 



Xorthern half of State ; roinnion ; less so in the 

 southern portion. April 2:'i-(.>ctober 26. Resem- 

 ''torisitwi.) "■ ''^'"^ iichulosus, but smaller: prosternum not cari- 

 nate and punctures or uppci- surface more distinct. 



505 (0315). Phiehydrus iiamh.toxi Horn. '11-ans. Amer. Eut. Sor.. XVII, 



IS'JO, 240. 



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

 ish-yellow ; head piceuus : disk of thorax with an iudefluKe 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 2:!-Sep- 



