70 Bulletin American Museum of Natural History [Vol. XLII 



The pupa is identical with that of perplexus, except that it is 

 generally smaller. Length, 4.5 mm.; width, 1.6 mm. 



Philydrus ochraceus Melsheimer 

 Plate XIV, Figure 11 



As this is our smallest Philydrus, the stages are smaller throughout. 

 The egg-case, which is characteristic of this genus, is much more flat- 

 tened than in the other species and the ribbon seems to be correspond- 

 ingly broader. The length of the case proper is 1.32 mm., its width about 

 the same, while the filament is twice as long, or 2.65 mm., in the speci- 

 mens at hand. An average of twelve eggs hatched from each case. 



Newly Batched Larva. — Length, 1.97 mm. ; width 0.288. mm. Chitinized parts 

 light yellow; and reddish eyes are distinct. Inner surface of the anterior piece of 

 each mandible distinctly serrate; the right anterior tooth dentate but the left anterior 

 tooth and the right posterior tooth simple. 



Philydrus cinctus Say 



Although I question whether it is the customary habit of this 

 species to omit the usual outer covering, yet such was the condition 

 found in One of the indoor aquaria. On June 4, 1915, a female laid a 

 mass of thirty eggs, perpendicular to a stone under some Cladophora 

 and with only the loose inner spinning of silk to cover it. Unfortunately, 

 the eggs did not hatch. The full-grown larva, measuring 7.9 mm., was, 

 however, captured. It had no serrations on the mandibles and the labro- 

 clypeus possessed a single tooth at the extreme right and left. Serrate 

 flap with four inconspicuous teeth Pupation occurred on July 20 and 

 the adult emerging on the 23rd was entirely light brown. 



Philydrus hamiltoni Horn 



An adult female taken on May 11, 1916, deposited an egg-case on a 

 moneywort leaf in the aquarium the 15th, and thirty larvse hatched out 

 on May 20 and 21. On the same day that the adult was collected, an egg- 

 case was taken in Vanishing Brook, where it was attached to a blade of 

 grass at the edge of the water. The egg-case proper is 3.4 mm. wide at 

 the middle and 2.3 mm. high. The filament, which spread out over the 

 surface of the leaf, measured 2.3 mm. in width and 6.8 mm. in length. It 

 is of about the same breadth throughout and in this respect is more like 

 ochraceus than nebulosus or perplexus. 



