238 [April 



in general ; there is a move or less distinct groove running from the 

 collare backwards, along the middle of the mesonotum ; on each side of 

 it there is a densely rugoso-punctate stripe ; the upper part of the me- 

 tanotum is also densely rugoso-punctate. 



Feet rather strong, fore coxae short ; spurs at the tip of the tibiae of 

 moderate length; e in podia large, distinct; last joint of the tarsi in the 

 male moderately excised at the basis on the under side and its shape 

 not modified. 



The male and female genitals arc very much like those of Oj/lindro- 

 i did a ; to the basal pieces of the male forceps is fastened, on each side, 

 a claw-shaped horny appendage, which in repose is folded backwards, 

 and closely applies to the upper part of the basal piece. The large 

 horny lamella or aculeus existing between the two halves of the forceps, 

 is somewhat differently shaped here ; it consists of three long, slender, 

 horny styles, connate at their bases and separate from each other to- 

 wards their tips; these tips are incrassated; (in (Jylindrotoma the three 

 styles are connate on their whole length, thus forming a lamella which 

 is tridentate at the tip). This lamella or aculeus is thrown out when 

 the forceps opens, and often, but not always, remains in this position 

 in dry specimens. This description of the forceps refers to T. nodicor- 

 nis, which I have observed in the living state; but judging from Dr. 

 Schiner's short description of the forceps of T. trisulcata, it must have 

 a somewhat similar structure. Of T. exsculpta I know the female sex 

 only ; the valves of the ovipositor both of this species and of Triogma 

 nodicornis are short and broad. 



The principal feature of the neuration, the course of the first longi- 

 tudinal vein, which does not end in the costa, but is incurved at its tip 

 towards the second vein, is the same here as in Cylindrotoma. The 

 auxiliary vein ends abruptly at the inner end of the stigma and has but 

 an indistinct connection with the first longitudinal vein. In some spe- 

 cimens, a slight vestige of an oblique cross-vein connects the latter part 

 of the first vein with the costa. Where this cross-vein does not exist, 

 there is no separation between the marginal and the costal cell. The 

 frequent absence of the small cross-vein seems to be a peculiarity of this 

 genus; the basal part of the submarginal cell thus comes in immediate 

 contact with the discal cell. This character is very frequent, although 

 not altogether constant ; T. trisulcata and T. exsculpta seem usually 

 to possess it; still, among seven specimens of the former, Schuinmel 

 {Beitreege etc. p. 106) observed one which had a small cross-vein, but 

 that on one wing only; with T. nodicornis this exception seems to be 

 more frequent, as among fifteen specimens which I have before me. 



