1920] Richmond, Studies on the Biology of the Aquatic Hydrophilidce 21 



Limnebius Leach 



• D'Orchymont gave the first description of the larva of Limnebius. 

 The eggs and pupa have not been described. 



Limnebius discolor Casey 



Three specimens were taken the latter part of June near the bank 

 of an alga -filled pool. The species is rare and has not been previously 

 reported from Cayuga Lake basin. It is difficult to recognize in the 

 field on account of its small size, but closer examination shows clearly 

 its resemblance to the Hydrobiinse type, with which it was formerly 

 classed. 



The eggs were laid on July 1 by captured specimens and one egg 

 hatched on July 8. As this was the only larva obtained, it is considered 

 inadvisable to give a description of it. However, the larva very closely 

 resembles L. truncatellus, which d'Orchymont carefully described. 



3. Hydrseninae 



Eggs laid singly. In Ochthcbius with or without a slight covering of looselv 

 applied silk but in Hydrcena covered with a blanket of closely span silk. 

 Larva as with Limnebiinae. 



Ochthebius Leach 



Ochthebius offers many interesting structures. 0. tuberculatus is 

 particularly unique and cannot be mistaken for any of the other species. 

 Besides 0. tuberculatus, 0. holmbergi and several other undetermined 

 members occur in the Cayuga Lake basin. 



All of them are, in general, quite rare. However, when once located, 

 many are usually collected in a very small area and one collecting ground 

 kept me well supplied from late April until winter set in. The soil in 

 this spot was especially sandy. Upon washing the sand with water and 

 pulling up and washing the roots of the vegetation which grew there, 

 many specimens were soon observed floating on the surface of the water 

 or clinging to floating debris. 



Haliday, 1855-6, was the first to figure a larva of this genus, namely, 

 0. punctatus. The latest and best study is that of d'Orchymont. He 

 worked out in detail the larva of 0. lejolisi, already described by Mulsant 

 and Rey, 1861, and worked over by Fauvel, 1865. D'Orchymont also 

 dealt with steinbuhleri and impressus. Rey, 1887, added 0. quadri- 

 coUi8 to the list of known larvae. 



