Vol. xxiv] ENTOMOLOGICAL NEWS. 125 



In terms of the system of classification proposed by Corn- 

 stock and Needham*, the usual tracheae present (Fig. i) are 

 the costa (c) which branches near its distal end and subcosta 

 (s) which lies close to the costa on the outer edge of elytron; 

 the radius (r), and media (m) which lie in the median por- 

 tion of the elytron; the cubitus (cu) which lies along the su- 

 ture and (a) the anal rudiment which lies next to the scutel- 

 lum. 



Deviations from the type shown in figure i are not numerous, 

 though in occasional individuals a number of large cross 

 tracheae takes the place of the posterior portions of the radius 

 and media as shown in figures 2, 3, 4, and 5. One of the main 

 trunks occasionally crosses over to the region of the next nearer 

 the suture (posteriorly). Branchings in this direction are com- 

 monest in other orders. This is shown in figures 4, 5, 8. 9, and 

 10. Bendings toward the outer margin of the elytron are rare ; 

 figure 2 (C. pur pur ea limb alls Klg.) shows the only one noted. 



Comstock and Needham, Part II, page 85, state that the 

 main stem of the radius, the most prominent vein of the wing, 

 usually separates into two main branches. In the Cicindelid 

 elytra, the radius is most variable. Branching in the middle 

 third of the elytron is evidently common (Figs. 7, 8, 9, and 10.). 

 The commonest type is shown in figure 7. About five per cent, 

 of the elytra of C. punctulata Oliv. show such variations. It 

 has been found in C. princeps var. ducalis Horn (India) (fig. 

 7; C. silvicola Dej. (Europe) (fig. TO) ; C. campestris (Eu- 

 rope) (fig. 9) ; C. tcnuipes Dej. (India) ; C. pamphilia Lee., 

 and C. dorsalis Say, as well as several other species of Cicin- 

 dela noted before definite records were kept. 



If the third elytra! trachea is rightly homologized with 

 the third of the wings of other orders, its tendency to branch 

 seems quite remarkable in view of the specialized conditions 

 of the wings concerned. Presumably this represents a rever- 

 sion to some ancestral type. It is likewise of considerable in- 

 terest to note the possibility of studying the physiological causes 

 of such divisions and of other variations in connection with 

 the development of the wings. 



* American Naturalist, 1899, pp. 43, 81, 231, 335, 413, 561, 769, 903. 



