CALIFORNIA ACADEMY OF SCIENCES. 315 



ORUS Casey. 



Orus punctatas Casey, exists in the greatest profusion 

 throughout the coast regions of California. Wherever there 

 is a rivulet or pond this species may be gathered in multi- 

 tudes amongst the rubbish along the banks. I have person- 

 ally taken hundreds of specimens during a few months' 

 residence. In these specimens the geniculation of the 

 antennas is seen to be as pronounced as in almost any other 

 genus of coleoptera, the angle between the axes of the first 

 and second joints being a right angle in the majority of 

 cases; I have represented this upon the plate. 



Of the two statements made by Dr. Horn (Ent. Arner. I, 

 p. 112), viz.: "The antennas are not geniculate," and " 0. 

 punctatus is from Owen's Valley, Cal. ;" the first is therefore 

 incorrect, and the second is at least open to doubt. 



In the genus Orus the anterior tarsi are feebly and 

 equally dilated in the male and female and clothed beneath 

 rather densely with short spongy papillas. Details of the 

 structure of various parts of the body are shown on the 

 plate. The genus is undoubtedly distinct from Scopceus, at 

 least far as the Californian representative is concerned, the 

 most salient differences being as follows : 



In Scopasus the antennas are straight, in Orus geniculate; 

 in the former the maudibles are tridentate, in the latter 

 4-dentate; in the former the ligula has at the tip three 

 approximate teeth , while in the latter there are plainly and 

 distinctly but two. 



In Orus the fourth joint of the maxillary palpi is exces- 

 sively small, in most specimens absolutely invisible except 

 under the most favorable conditions; when these conditions 

 of light, position, etc., are attained, it is seen to be very 

 oblique, thin and subulate, and to lie far within the large 

 and deep oval excavation in the tip of the third joint, not 

 projecting visibly beyond its margin, so that it is generally 

 entirely invisible when viewed laterally. The labrum is 

 strongly quadridentate. 

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