IQOl] ENTOMOLOGICAL NEV/S. 3 



lobe square, 4.5 mm. long and 5.5 mm. wide, abruptly narrower near the 

 posterior end ; anterior edge with a larger tooth on either side of the 

 median line and about ten smaller ones on either side ; extending pos- 

 teriorJy to half way between the bases of the first and second pairs of 

 legs ; lateral lobes wide, opposed edges straight, notched with small 

 serrations. 



Prothorax angular, high, dorsum and sides meeting at nearly a right 

 angle, the edge produced laterally and clothed with bristly hairs ; all of 

 thorax scantily clothed with short hairs. The thorax widens and deepens 

 from the prothorax to the metathorax at the base of the third pair of legs 

 where it is as wide as the abdomen in its widest part.- The front wing 

 cases extend to the posterior edge of the fourth abdominal segment ; 

 apparently the costas lie almost parallel ; the cases of the hind wings 

 reach to the middle of the fifth segment. Legs very robust, strongly 

 formed, angular, especially the femora, the edges clothed with bristles ; 

 a deep depression in the mesosternum, between the second pair of legs, 

 to accomodate the hinge of the labium. 



Abdomen spindle-shaped, 23 mm. long, widest at the fifth segment 

 where its width equals one-half its length, low, flattened, the sterna 

 scarcely convex, terga convex, width of fifth segment ii mm., depth 5 

 mm. Segment nine with a lateral posterior spine ; on segments ante- 

 rior this spine grows successively smaller, not present on first three 

 segments. The mark, on the sternum of the ninth segment, of the ovi- 

 positor of the imago is conspicuous. On dorsum of segment five are two 

 tufts of bristles, one on either side, separated from each other by about 

 one-third the width of the segment, and placed a litttle nearer the pos- 

 terior than the anterior margin of the segment ; these tufts persist from 

 the fifth to the ninth segments, the tufts on each segment successively 

 approaching each other more closely till on the ninth they stand just on 

 either side of the median line ; each tuft is placed on an irregular eleva- 

 tion and in some cases seems to be double. Appendages short, middle 

 one tapering ; apex truncate, on either side produced to form a short 

 tooth ; laterals shorter, conical ; inferiors compressed, wide, rounded 

 triangular, longer than the middle appendage, the lower edges and the 

 posterior ventral edge of the tenth segment between them bearing many 

 4ong stiff, yellowish hairs. 



Described from the exuvia of the reared female of June 4, 

 1900 ; both exuvia and imago are in my collection. 



EXPLANATION OF PLATE L 



Fig. I. — Dorsal view of Nymph of Tachopteryx Thoreyi Hagen, Pitts- 

 burg, Pa., June 4, 1900. 



Fig. 2. — Dorsal view of the terminal abdominal appendages. 



Fig.3 . — Median portion of the sternum of ninth abdominal segment 

 showing the prominences for the ovipositor of the imago. 



Fig. 4. — Labium of the exuvia. 



