NORTH AMERICAN COLEOPTERA. 261 



Elytr?. striate, or striato-puuctate HYDROBIUS. 



Elytra with confused puiictuatioD. 

 Posterior femora glabrous. 



Anteiinse 9-joiuted ; mesosternum simple ANAC^NA. 



Antennse 7-jointed ; mesosternum protuberant METACYMUS. 



Posterior femur punctulate, opaque and pubescent; mesosternum protuberant. 



PARACYMUS. 



In addition to the above Tritonus Muh. and Limnoxenus Motsch. 

 have been suggested, which seem perfectly congeneric with Hydro- 

 bius as limited above. Creniphilus Motsch. was suggested to include 

 two species afterward separated by Thomson as Anacjena and Para- 

 cymus. 



Crenitis Bedel should have its place in the table near Paracymus. 

 Of it Bedel writes as follows : " Distinct from Hydrobias, Paracymus 

 and Anaccena by its scarcely spinulose tibite, and from the first two 

 especially by its simple mesosternum and from the last by its pro- 

 thorax without basal marginal line." 



Unfortunately, these characters have no value when the species 

 of our fttuna are taken into consideration as will be learned in the 

 following pages. 



^Moreover, the antennae are said to be 9-jointed, but a specimen 

 sent me by Dr. Sharp plainly shows 8-jointed antennae as in Creni- 

 phi/us vionticola. It seems to me that the species on which Crenitis 

 is founded {punctato-striatus Letz.) sliould take its place in the genus 

 Creniphilus and be placed near monticola. 



Dr. Sharp finds it advisable to include all the species under one 

 generic name, although he separates ]\Ietacymus by its 7-jointed an- 

 tenna-. 



This genus seems surrounded with much doubt, and while he has 

 suggested in a recent letter that it is related to the Derallus series 

 (J. e. near Berosus) the description and the relationship in which it 

 has been placed hardly warrant such an inference. 



While the views expressed later on will be found in accord with 

 those who are not willing to retain Anacfena and Paracymus dis- 

 tinct, there will be disagreement with those who unite all under Hy- 

 drobius. Inasmuch as it is impossible to retain those two genera as 

 distinct, it seems to me at least inconvenient to use either name for a 

 union of the two, I have, therefore, reverted to an undescribed name 

 by Motschulsky, which had for its types the two species constituting 

 the types of the separate genera. Other remarks on this subject will 

 be found under Creniphilus. 



