234 JOURNAL New \'ork Entomological Sociktv. [Voi. x. 



The locality they fre(iuent in the Park (and where thev were abun- 

 dant) is a small lake full of vegetation. I found them among the 

 past year's dead leaves in a little cove which was later massed with 

 vegetation. This place was teeming with agrionid nymphs, which 

 furnished them abundant food. 



In Staten Island a few were found in Cape Henlopen pond ; they 

 were, however, much more abundant in the vegetation in the rock- 

 pools of an abandoned quarry. The temperature of the water was, 

 of course, low, because of the season, and the insects seemed to be 

 seeking shelter among the vegetation. 



The specimens taken in the spring bred in my aquaria, but unfor- 

 tunately I was unable to take them beyond the third instar. From 

 the size of this nymph and of others that I have collected, it might 

 seem that there are at least five instars, if not six. 



This is by far the most common species locally and can be found 

 without any difficulty. 

 Notonecta variabilis Fieb. 



"Bead : notocephalic lateral margins diverging curvedly from the narrow base, 

 vertex about three times as wide as synthlipsis. Pi onotum : width of posterior mar- 

 gin not quite twice as great as the length of the pronotum. Heiiielytra : very variable. 

 Alar nervures pale golden yellow. Pedes and abdomen as in X. nuditlata Say. 

 Long. 8.9 to 10 mm.; lat. 3. to 3.4 mm." 



This interesting species I first took on the Palisades, one speci- 

 men only. On election day (November 4 ) of this year, I collected 

 it in large numbers at Van Cortlandt, and found it clinging to the un- 

 der surface of dead leaves in the water. 



It looks very much like a small specimen of N. iindulata var. mac- 

 ulata, but the size and the notocephalon serve to determine it. The 

 largest variabilis I have measured is only 10 mm., while the shortest 

 undulafa var. maciilata exceeds 11 mm. 



This species has also been taken in Staten Island by Mr. Davis and 

 myself. 



It is of interest to note that on one specimen of this I found a para- 

 site, fastened to the dorsum of one of the abdominal segments. I 

 shall describe this later. 



This species is in part N. varibilis Fieb., and is considered by Pro- 

 fessor Uhler to be a variety of uudulata. As stated before, I have 

 accepted Kirkaldy's classification, and on comparison of characters, 

 it would seem to me that his differentiation of species is good. 



