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Vol. XLVI. LONDON, JUNE, 1914 No. 6 



LIFE-HISTORY NOTES ON TWO COLEOPTERA 



(PARNID^E). 



BY ROBERT MATHESON, ITHACA, N. Y.* 



Psephenus lecontei Lee. 



Although many notes, brief references, and figures of the 

 larva (fig. 3), water penny, of this beetle have appeared from 

 time to time in American literature, no consecutive account of its 

 life-history has as yet been published. As this extremely interest- 

 ing species is found very widely distributed in America and is of 

 considerable interest on account of its peculiar larval form it seems 

 to me that a short account, though gathered from desultory obser- 

 vations extending over the past two years, would not be out of 

 place at this time. 



Ordinarily the beetles are not usually observed by the col- 

 lector though practically everyone who has any interest in ento- 

 mology has seen the peculiar larvae on the under side of stones, etc., 

 in any of our rapid streams. In some streams they are very 

 abundant and usually so in the swifter-flowing portions, particularly 

 where the stones break the surface of the water into ripples. Here 

 also the beetles are found, often in considerable numbers, but 

 not in the water. H. G. Hubbard, in the American Entomologist 

 for 1880 (p. 73), well described the habits of the adults. Both 

 males and females may usually be found, particularly during the 

 heat of the day, gathered upon stones in mid-stream which just 

 break the surface of the water. They are very active, flying 

 about, and chasing one another over the stones. I have never seen 

 them plunge into the water nor suffer themselves to get wet. 

 They are usually very easily frightened and one has to approach 

 cautiously with a net in order to catch them; for they take sudden 

 flight and one can scarcely follow their movements. However, if 

 one will look around carefully they will usually be found only a 

 few feet away actively playing on another stone. 



*Contribution from the Entomological Laboratory of Cornell University. 



