LIBELLULID^. 



597 



much as in the Perlarice, and probablj'^ with the sides pro- 

 tected near the base by the deflected marginal and scapular 

 (subcostal) areas." Scudder shows that while the venation is 

 much the same as in Hemerobius, as stated by Professor Dana, 

 it also resembles that of the Sialidce and Ephemeridoi and 

 Lihellulidce. Gerstaecker thinks that Hemeristia "at least 

 stands nearer to the Ephemeridce than to any other family." 

 (Bronn's Klassen und Ordnungen des Thier-Reichs, vol. v.) 



LiBELLULiD^ Latreille. Dragon-flies, Devil's-darning-nee- 

 dles, or Mosquito Hawks, are readily known by the enormous 

 head and thorax, with the remarkably long, slender, cylindrical 

 abdomen. The head is large and globular, with immense eyes 

 often encircling the head. The large square thorax is remark- 



able for the small size of the tergal parts, while the pieces 

 composing the flanks are greatly enlarged, rising up especially 

 in front, talving the place of the prothorax, which is usually 

 very large in the Neuroptera generally, but is in this family 

 greatly aborted, as these insects scarce!}^ ever walk. As in 

 the Ephemeridoi the antennse are short and setiform, but 

 the mouth is furnished with palpi. The wings * are large, 



*FiG. 579. Venation of a fore wing of Gomphns. Veins. — a, a, costal vein; b, 

 subcostal vein ; c, c, median vein ; d, submedian vein ; e, postcostal vein. Sectors — 

 (branches springing from areas, veins, cross-veins, or other sectors), fff, princi- 

 pal sector; g, nodal sector; h, snbnodal sector; k, median sector; mm, short sec- 

 tor; n, upper sector of the triangle (normally a xirolongation of d); o, lower 

 sector of the triangle (noi-mally a prolongation of e): o', o", its branches. (The 

 figure gives an angle where o' ))ifurcates from o, %vhich should have been a flow- 

 ing curve. Both n and n should have been engraved as springing from the lower 

 angle of the triangle, t.) Cross-veins. — p, nodus; q, arc or arculus; rrr, - - - ante- 

 cubitals. (The basal antecubital is « rongly engraved as dislocated with tliat of 



