REHN AND HEBARD 61 



sulcus proximal only; cerci short, teretf;; ovipositor very slightly longer than 

 the caudal femora, straight, moderately robust, subequal in depth, not tapering 

 (except on proximal third) and rather sharply narrowed to the apex which is 

 ventro-median in position; subgenital plate sharply and deeply divided, the 

 lateral portions of the plate with their tips regularly and sharply rectangulate. 

 Caudal femora in length slightly more than twice that of the pronotal disk, 

 ventro-internal margins of the caudal femora with single spines. 



Paratijpic Series. — We have indicated as paratypes a series 

 of four males and seven females taken at the type locality and 

 in company with the type and allotype. 



Morphological Notes. — The variation in form found in this 

 species is very considerable and has proved quite puzzling. 

 One of the most striking features is the variation in the general 

 form and proportions of the pronotal disk; this is very great, 

 probably the greatest found in the genus, and the two extremes, 

 both of which are present or closely approximated in each of the 

 series from Arlington and Orange, Virginia, are so different 

 that it requires careful examination to show they are not 

 different species. In the male sex the proportion of greatest 

 caudal width of disk to length of same varies from 67 to 74 per 

 cent, and in the female sex the ratio is 62 to 71 per cent. The 

 form of the disk is also influenced by the degree of constriction 

 at the cephahc fourth, this and the general curve of the lateral 

 carinae of the disk varying independent of the ratio of greatest 

 breadth to length. The least width of the disk is contained 

 from but little more than twice ( cf ; Broad Top Mountain, Penna.) 

 to nearly thrice ( 9 ; Arhngton, Va.) in the greatest length of 

 disk. The cephahc margin of the pronotal disk varies from shal- 

 lowly angulate-emarginate to subtruncate, the latter condition 

 unusual. The caudal margin of the pronotal disk is considerably 

 arcuate in the male, varying in the female from similarly arcuate 

 to truncato-arcuate. The humeral sinus of the lateral lobes is 

 always well indicated. The tegmina of the male show no appre- 

 ciable variation in length. The prosternal spines are always 

 rather short, but vary greatly in length, and while occasionally 

 quite aciculate are more frequently but brief dentiform projec- 

 tions, and more rarely mere subobsolete nodes. The meso- 

 sternal lobes are rectangulate with a subtuberculate angle. The 

 disto-dorsal al)dominal segment of the male shows an apprecia- 

 ble amount of variation in the degree of angulation of the median 



TRANS. AM. ENT. SOC, XLII. 



