ERPETOGOMPHUS. 165 
6. Erpetogomphus crotalinus. 
Ophiogomphus crotalinus, Hagen, in Selys, Bull. Acad. Belg. xxi. pt. 2, p. 40 [21] (1854) °. 
Erpetogomphus crotalinus, Selys and Hagen, Monogr. Gomph. p. 72 (excl. syn.), t. 4. figg. 5 a-1 
(details g 9) (1858)? ; Selys, Bull. Acad. Belg. (2) xxviii. p. 174 [11] (1869) °. 
Gomphus crotalinus, Hagen, Syn. Neur. N. Am. p. 101 (excl. syn.) (1861) *. 
? Erpetogomphus boa, Selys, Bull. Acad. Belg. (2) vii. p. 537 [11] (1859) (? only)’. 
The “deux bandes médianes”? are entirely absent in the present material, the third tibie may have a 
superior black line as well as the first and second*; pterostigma surmounting 33-64 cells. 
Hab. Muxtco (Mus. Berol. 124) (M. C. Z.: 1 ¢ labelled “ tineatus” “ Mus. Berol.” ; 
U.S. N. M.: 2 3), Chihuahua (If. Kerr: 1 3), Durango (Barrett, coll. P. P. C.: 
7 3), Guadalajara (Schumann: 43,49, one of the males with label “ Herp. 
crotalinus” in Hagen’s hand; McClendon, coll. P. P. C.: 28,12), and Zapopan 
(coll. W. L. Tower: 12 ) in Jalisco [1 ], Mexico city [1 2 ] (Schumann), Cuernavaca 
(Barrett, colls. Adams, P. P. C.: 83,2 9; coll. McLachlan: 1 3, with label 
“ Herpetogomphus erotalinus, Hag.,” in MclL.’s hand), Oaxaca (L. O. Howard, U. S. 
N. M.: 1 2). 
Taken from May to October. (See also under H. boa below.) 
7. Erpetogomphus boa. 
Erpetogomphus boa, Selys, Bull. Acad. Belg. (2) vii. p. 537 [11] (1859) (¢ only) *. 
Gomphus boa, Hagen, Syn. Neur. N. Am. p. 100 (1861) ?. 
Hab, Mexico, Vera Cruz (Sallé ! 2). 
I have not been able to find this species in the material before me. I am inclined 
to think that the female which de Selys described as boa may not be conspecific with 
the male, owing to the difference which he gives in colour of the tibie of the two 
sexes. Such a difference is not met with in the two sexes of any other member of this 
genus. The supposed female of 40a agrees strongly with that of crotalinus and is, I 
venture to think, really that species. See also the remarks under sipedon. 
8. Erpetogomphus sipedon, sp. n. (Tab. VII. figg. 34, 40, 42.) 
¢o unknown. 
Q. Head and thorax pale green, the following dark brown: a spot on each side of the dorsum of the middle 
prothoracic lobe, an antehumeral stripe not reaching to the antealar sinus above but to the anterior 
mesothoracic margin below, confluent near its upper end with a superior humeral spot which is prolonged 
downward to half, or the entire, length of the humeral suture. 
Abdomen chiefly blackish, the following pale green or yellow: a mid-dorsal stripe, for the entire length of 
segments 1-6 and four-fifths length of 7, trilobed on 2-7, confluent with a pale transverse basal ring 
on 4~7; sides of 1-9 inferiorly, all of 10. 
Appendages a little longer than segment 10, slender, tapering to acute apices, pale yellow. Vulvar lamina 
(see fig. 34). 
Femora, pale green, with a dark brown stripe anteriorly for the entire length of 1, the greater distal part of 2, 
and the distal third of 3; tibie and tarsi black, the former with a yellow line on the anterior and 
posterior edges or on the anterior edges only. 
