AQUATIC INSECTS IN THE ADIRONDACKS 439 



Ophiogomphus carolus Needham 



Plate 20, fig. 1-4, 6, 7 



1897 Opbiogomplius caroius Needham, Can. ent. 29 : 183, pi. 7, fig. 1, 2, 



3, 4, 6, 7 

 1899 Ophiogomphus carolus Needham, Can. ent. 31 : 235-36, pi. 5, fig. 



1 and 28 



This species, abundant at Ithaca N. Y. and taken at several other 

 places in the state, was not met at Saranac Inn. It is a very secre- 

 tive species, few imagos being seen, even where nymphs are excessively 

 abundant. Like the preceding species, the nymphs prefer the sandy 

 beds of running streams. 



Nymph. Total length 26 mm; abdomen 17 mm; hind femur 4.5 

 mm; width of head 5 mm, of abdomen 7.5 mm. 



Body moderately depressed, widest across the sixth abdominal seg- 

 ment, suddenly narrowed on the ninth segment.' All ventrolateral mar- 

 gins closely fringed with soft hairs. Color yellowish, the surface abund- 

 antly sprinkled with brownish granulations visible under a lens. 



Abdomen with lateral spines on segments 7-9, a little increasing in 

 length posteriorly, but on the ninth segment distinctly shorter than the 

 loth segment. Dorsal hooks on these same segments developed as small 

 blunt posteriorly directed prominences, which hardly surpass the narrow, 

 bare apical band on their respective segments, longest on segment 9, and 

 decreasing in size anteriorly so as to be barely represented on segments 



6, 5. 4; 



Labium as in O. aspersus, but with the 12 to 16 teeth on the 

 inner margin of the lateral lobe a little longer and more angulate at tips. 



Easily distinguished from the nymph of O. a s p e r u s by the unequal 

 development of the dorsal hooks on the abdominal segments. 



This species is very common at Ithaca N. Y. Few imagos have been 

 taken at large, and, indeed, they are rarely met with ; but the nymphs 

 may be collected by hundreds from Six Mile creek in spring, and they 

 are very easily reared. 



Ophiogomphus johannus Needham 



Plate 20, fig. 5 

 1897 Ophiogomphus johannus Needham, Can. ent. 29 : 182, ^jI. 7, fig. 5 

 1899 Ophiogomphus johannus Needham, Can. ent. 31 : 235, pi. 5, fig. 9, 

 18 and 27 



The type of this species in the Cornell university collection is from 

 Wilmurt N. Y., and was collected by Prof J. H. Comstock. Since 

 describing this somewhat immature specimen, I have seen specimens col- 

 lected in Maine by Prof Harvey, and in western Pennsylvania by Mr 

 Williamson. From these I learn that the terminal abdominal append- 

 ages of the male are not well represented in the figures I have published.^ 



1 Can. ent. 1897. 29: 182, pi. 7, fig. 9, 18. 



