236 H. A. HAGEN. 



tlrely covered with black spines, which character separates this species 

 from all others (fig. 16). 



Length of abdomen of the male 20-24 mm., hindwing 21-29 mm. 

 The average dimensions of Massachusetts specimens are mostly near 

 the smaller nunibers, of the Western specimens near the larger. 



Vulva with two distant lobes, and behind them two accessory palps 

 in the middle of the segment (fig. 23). 



The basal spot on hind wing is small and emarginate below; all 

 the others are only beginning (seen with strong lens). The wings 

 of the female vary much more, the triangular spot on hindwings is 

 sometimes larger, also in subcostal space, and in the forewings more 

 or less long, sometimes divided into two transversal spots, the wings 

 sometimes yellow to triangle or farther, and sometimes smoky. 



This species is the most common of its genus in the Northern parts 

 of the United States. I have not seen it, however, from the Colorado 

 Mountains where Diplax scotica flies. 



o 



I possess the nymphte of pectoralis and triedra raised by myself, 

 and of dubia raised by Heyer. The nympha of triedra differs from 

 the others and is nearer to Cordiilia. The descriptions are not yet 

 published. I think that I have also the nympha of intacta. 



EXPLANATION OF PLATE X. 



Fig. 1. — Pattern of coloring of abdomen of Leucorhinia pi'oxima. 

 " 2. — Inferior apjiendage of L. frigida %; 2A, its tip. 

 " 3.— " of L. glacialis %. 



" 4. — " of L. proxima % . 



" 5. — '■ of L. rubicunda % from Wilui, Siberia. 



" 6. — " of L. intacta % . 



'• 7. — Appendages of L. frigida % , viewed from the side. 

 " 8. — Hamule of L. intacta % , viewed from below. 

 " 9. — " of L. proxima % (form perversa), viewed from below. 

 •' 10. — " of L. horealis % , viewed from the side. 

 '• 11. — " of L. rabiciuida % , viewed from the side. 

 '• 12. — " of L. dubia % , viewed from the side. 

 " 1.3. — " of L. hudsmiica % , viewed from the side. 

 " 14. — " of L. glacialis % , viewed from the side. 

 " 15. — .-1, B. C. Three patterns of coloring of labium of L. intacta % . 

 " 1 6. — Tubercules on the "jiiece auterieure" of L. intacta % . 

 " 17. — Base of hindwing of L. frigida. 

 " 18. — A, B. Valves of L. hudsonica f. 

 " 19.—A-F. " of L. dubia 9 . 



" 20.— '• of L. frigida 9 . 



" 21. — " of L. borealis 9 • 



" 22. — " of L. proxima 9 • 



" 23.— " of /.. intacta 9 . 



a, basal branch of hamule. 



6, apical branch of hamule. 



art, articulation of basal branch. 



m, membrane lining the hamule. 



X, triangular polished projection. 



a, (figs. 8, 9) basal branch of hamule, separated and viewed from side 



