SCUDDER ON FOSSIL INSECTS. 761 



B. cuspidains Chevr., and, unlike all Berosilhsixe seen, are nearly devoid 

 of any sigu of punctuation ; faint traces only can be seen when magnified 

 twenty-five diameters. As not unfrequently happens in EydropIiiUdce, 

 altbough I have not noticed it in Berosus, a short supplementary stria 

 originates near the base of the second stria, pushing it a little to one side, 

 and runs into the fi.rst stria a short distance from the base of the elytra. 



Length of elytron 4.5""^ ; breadth 1.4'""^. 



Laccobius elongatus. — A single specimen and its reverse (Nos. 81*, 13Gs), 

 collected by Mr. Eichardson, but overlooked in my former i)aper on the 

 Coleoptera of the Eocky Mountain Tertiaries,* exhibit the elytron of a 

 slender species of LaccoMus. It is more than two and a half times longer 

 than broad, and is furnished with thirteen equidistant, delicately puuc 

 tured, faintly impressed striae, the punctures of whicli are more apparent 

 on the basal than on the apical half; the inner stria is as distant from 

 the sutural border as from the neighboring stria, while the outer is 

 scarcely separate from the outer margin. The species is very large, and 

 also very slender, for a LaccoMus, in which genus, however, I am inclined 

 to place it, from the large number of punctured striae. The elytron has 

 much the general appearance of that of a Lehia, but the number of striae, 

 of course, forbids such a reference. 



Length of elytron 2.9""" ; breadth 1.1"". 



PMlhydriis primcevus Scudd., Bull. TJ. S. Geol. and Geogr. Surv. Terr, 

 ii, 78. — A single specimen, found by Mr. Eichardson. 



PJdlhydrus spp. — Two specimens (Nos. 4033, 4042) of a second species 

 of Philliydrus were found by Mr. Bowditch and myself, but neither of 

 them very perfect, representing little else than elytra, and these rather 

 obscurely preserved. The larger species has smooth elytra; the elytra 

 of the other have eight delicate striae, which apparently are not punc- 

 tured. Possibly one or both should be referred to Hydrohius. 



Length of elytra of larger species (No. 4033) 4"" ; breadth of body 

 3.2"". 



Length of elytra of smaller species (No. 4042) 3.75"" ; breadth of 

 body 3"". 



Rydrohius decineratus. — A single specimen (No. 4007) exhibits the 

 dorsal surface, but with part of the thorax gone. It represents a species 

 a very little larger than R.fuscipes Curt, of California, and is apparently 

 allied to it, though slenderer; the head and eyes are as in that species ; 

 the thorax shorter and the elytra longer, and more tapering at the tips, 

 the extremitiesof which, however, are not preserved; they are furnished 

 with eight delicate striae, in which the punctures are scarcely i)ercept- 

 ible, even when magnified ; the surface otherwise appears to be smooth, 

 but is not well preserved. The scutellum is as in the recent species 

 mentioned. 



Length of body 7.5"", of elytra 4.75"" ; breadth of body 3.6"". 



'Bulletin of this Survey, ii, No. 1, 77-87. 



