398 Annals Entomological Society of America [Vol. XI, 



Determination of what stage a larva was in depended upon counts of 

 antennal segments. Lack of sufficient material precluded study of 

 instars directly following the above. Whether there is a similarly 

 graduated increase and constancy for all instars cannot consequently be 

 stated. A continued increase in number (without corresponding large 

 increase in comparative length of the antennas) seems certain though, 

 for in the full grown larva, a big total of 120 to 125 segments exist. This 

 is a striking feature, and one which does not correspond with the con- 

 dition in larvse of Helodes and Cyphon, (11). 



Last Instar (Fig. 4). 

 The average full grown larva has a length of 7 mm. The specimen 

 figured, with a length of 7.33 mm., was of maximum size. The body 

 generally is as described for earlier instars, but is more flattened dorso- 

 ventrally. Its shape can be characterized in short as that of the silver 

 fish, Lepisma sp., a similarity that is true also of the antennae. Color a 

 dark, uniform brown. Head normally defiexed. Antennas setaceous, 

 very long and slender, three-fourths as long as body, of 120-125 seg- 

 ments ; segments 1 and 2 much longer than any of those following. Leg 

 has long, heavy coxa. 



Pupa (Fig. 5). 

 The pupa is elongate-rounded, about 4.5 mm. in length, and of 

 cream white color. It is attached by its anterior end to the lower 

 surface of a Lemna leaf, and hangs freely. ' The last larval skin may or 

 may not remain attached to the pupa; if it remains it may be for either 

 a short period or even beyond the emergence of the imago. 



Adult (Fig. 6). 



The adult (length 3 to 3.5 mm.) was originally described by 

 Guerin (4). Although his work was not available, the descrip- 

 tions of Horn (5), and Blatchley (1), obviate the need of tech- 

 nical description here. The most characteristic features which 

 are easily noted in this beetle are its very broadly oval shape, 

 its short, much defiexed head, and its greatly swollen hind 

 femora. 



Although the color of very many of the specimens of beetles 

 is, as described, "uniform piceous or nearly black, moderately 

 shining," (1), of a considerable number of others it is a uniform 

 dull, dark brown. The beetle is "sparsely pubescent," but the 

 brown ones are relatively more pubescent than the black. The 

 brown ones as a group are also larger, having all about the 

 maximum length of 3.5 mm., while the black are on the whole 

 3 mm. in length. While Horn (5), says that the claw on the 

 tarsus is simple, in all beetles examined in this study, the tarsal 

 claw was double. 



