1920] Richntojid, Studies on the Biology of the Aquatic Hydrophilidoe 71 



Newly Hatched Larva. — Length, 2.66 mm.; width, 0.39 mm. Chitinized 

 parts mostly brownish; the anterior of the head, however, except the palpus of the 

 maxilla, light yellowish. Inner surface of the anterior piece of each mandible serrate. 

 The right distal inner tooth serrate but the distal left and the right proximal inner 

 teeth are simple. The serrate flap of the labrum is fairly conspicuous and with a very 

 prominent tooth at the left. 



Ancena Thomson (ex parte Cryniphilus 1 ) 



There is hardly a stream or pool in the vicinity of Ithaca that will 

 not yield the only representative of this genus which frequents our 

 waters. Anccena infuscata. The specific name is well applied but close 

 examination is necessary to be absolutely positive that it is not the closely 

 related Paracymus subcupreus. The most ready character for their 

 separation lies in the nature of the hind femur which in infuscata is 

 densely punctulate and pubescent, except near the tip; while in sub- 

 cupreus it is smooth, finely strigose, and not pubescent but with a few 

 scattered punctures. 



Although very often taken together, yet some collecting grounds will 

 show one or the other of these species to be in predominance, A. infus- 

 cata being the more numerous as a rule. The adults are particularly 

 abundant during certain seasons. The spring season collecting brings 

 the richest harvest and hundreds of them may be taken in single clumps 

 of grass, the roots of which are submerged in the waters of little pools or 

 streams during the week following the spring flood. They rarely seek 

 the sunlight, at least in cool or cloudy weather, but hide beneath the 

 blades of grass, leaves, or debris at the shore-line. One day, however, a 

 group of them was noted dotting the upper surface of some submerged 

 stones; they were apparently basking in the sunlight and very much 

 resembled small scale insects. When searching for their place of hiber- 

 nation, several were taken in April a few feet from the water under 

 stones and pebbles. 



D'Orchymont described the larva of Ancozna limbata. This species 

 closely resembles Paracymus subcupreus but differs considerably from A. 

 infuscata. 



Ancaena infuscata Motschulsky 



Plate XV 



The egg-cases are similar to those formed by Laccobius, from which 

 they are separated with difficulty. My notes for the season of egg-laying 

 give only the month of May. The number of eggs, enclosed in the case, 



2 This i3 the original spelling of the genus. Later authors incorrectly used Creniphilus. 



