36 ENTOMOIvOGICAIv NEW*.. [Feb./lQ 



Erpetogomphus diadophis ? Calvert (Plate III, figs. 10-12). 

 Cayuga, house, October 25, i ? . Very similar to the paratype of the 

 species (in coll. Acad. Nat. Sci., Philadelphia) in the shape of the 

 occiput, the very reduced vulvar lamina and the characteristic semi- 

 circular groove on the sternum of 9. It is smaller (abdomen 29, hind 

 wing 24, costal edge of stigma, front wing 3 mm.) and the annulate 

 appearance of the abdomen, on 2)-7^ due to the presence of a trans- 

 verse median yellow band in diadophis, is on first examination not 

 distinct, owing, perhaps, to the apparently less matured coloration 

 of the body generally. I believe that I can recognize the annuli on 

 segments 6 and 7, at least. Color differences, due, possibly, to the 

 same cause (immaturity), are the smaller extent of the dark para- 

 median stripes of the thorax (mesepisternum) and of those at the 

 humeral, at the obsolete first lateral and at the second lateral sutures, 

 in comparison with those of the paratype of diadophis, as our figures 

 show. (PI. Ill, figs. 10 and 11, 7 and 8). 



The similarity of the vulvar laminae in the two specimens is not 

 identity. The two lobes of the lamina in the Cayuga female are rel- 

 atively more widely separated than in the paratype (cf. PI. Ill, figs. 12, 9), 

 although the absolute measurements are as follows : from apex of 

 right lobe to apex of left lobe, Cayuga $ .3 mm., diadophis $ para- 

 type .4 mm. ; length of lobes measured from the anterior (a) of the 

 two transverse lines shown in PI. Ill, figs. 12, 9: Cayuga 9 .2 mm., 

 $ paratype .3 mm. 



In addition to the possession by both females of the semicircular 

 groove on the ventral side of segment 9, mentioned above and shown 

 in our figures quoted, both females show a transverse groove (0 on 

 the sternum of 8, anterior to the vulvar lamina, and situated in both 

 at three-fourths the length of the sternite, measuring from its anterior 

 extremity to the same line a. 



Neither the paratype of diadophis nor the female from 

 Cayuga is in perfect condition ; the former, ever since I re- 

 ceived it from the late Mr. McLachlan, has lacked segment 

 10 and the abdominal appendages. Without additional ma- 

 terial it is not possible to decide whether these two females 

 are conspecific or not. All that I am able to say at present 

 is that they appear to be very near to each other on the basis 

 of structural characters, while diflfering in size and in details 

 of coloring. 



Epigomphus subobtusus Selys. Cayuga, dark forest, April 25, 

 1 ? ; forest, May 3, i teneral $ ; forest, i $ over stream, i teneral 9 ; 

 stream in dark forest. May 28, i ^ , "oblique black and greenish blue 



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