NATURAL SCIENCES OP PHILADELPHIA. 395 



antehumeral stripe attaining the anterior edge, and a brown humeral stripe on 

 the suture ; pleura pale or yellowish, with a rather narrow brown stripe before 

 the spiracle, which last is edged with black, and a similar one on the suture be- 

 hind the spiracle, sometimes subobsolete ; antealar sinus black in front; ster- 

 num pale. Abdomen brown black, with joints 7 9 but slightly dilated be- 

 neath, and marked with yellow on the dorsum as follows : joint one, with a 

 large longitudinal oval spot, confluent laterally and basally with a small spot, 

 and together with the three small spots covering its entire length ; two, with a 

 lanceolate spot on its entire length; 3 8, with a narrow cuneiform basal spot 

 about 1 lj millimetres long, sometimes throwing out behind a narrow line, 

 which is often interrupted before the medial suture of the joint, and never quite 

 attains the tip ; joints nine and ten with a narrow basal membranous line ; late- 

 rally joints one, two and ten are yellow, except behind the earlets, which are 

 yellow, with a few small black thorns on their posterior edge, and except also 

 the tip of joint two ; joints 3 6 have a small basal triangular yellow spot, be- 

 coming gradually smaller, until in six it is subobsolete, and joints 7 9 are sub- 

 marginally yellow, the yellow in seven and eight more or less mottled with 

 brown at tip; venter pale yellow towards the tip, where it is visible. Superior 

 abdominal appendages half as long as the ninth joint, which is nearly four times 

 as long as the tenth, black, slender, tapering, conical, approximate at base, di- 

 varicate, slightly curved downwards for three-fourths their length, the remain- 

 ing fourth straight, with an inferior carina much curved outwards, and ascend- 

 ing their sides to about half their length, whence it again curves inwards and 

 is produced to their tips ; inferior appendages one-fifth shorter and more robust 

 than the superiors, pubescent, black, pale at their internal base, approximate 

 at base, more widely divaricate than the superiors, scarcely tapering, with the 

 lower surface rounded and the upper flat, and finally, just before they attain 

 their furthest limit, hemispherically excavated above, when the tip turns sud- 

 denly and almost squarely upwards for J or J millimetre, and terminates 

 acutely. Legs brown black, coxae and trochanters yellowish, intermediate 

 trochanters brown beneath ; anterior femora yellowish inferiorly and poste- 

 riorly ; tibiae and tarsi in the more mature individuals, deep black. Wings 

 hyaline ; veins and cross-veins all, including the costa, black ; membranule 

 cinereous; pterostigma pale brown, surmounting A\ 5| cells. Antecubitals 

 12 15; postcubitals 9. Two discoidal areolets, commencing always with three 

 behind, sometimes with three before. 



The $ differs from the $ in the vertical vesicle being strongly tubercled at 

 each end, between which and the eye is a robust, conical, black thorn, rising 

 as high as the ocellus ; the dorsal thoracic stripes are in one specimen and on 

 one side only confluent with the anterior margin ; the cuneiform dorsal spots of 

 the abdomen are sometimes subobsolete : and the abdomen is marginally yellow 

 for its entire length, with an abbreviated submarginal yellow vitta on joints 3 

 6, which is sometimes confluent with the yellow margin, sometimes sepa- 

 rated from it by a black line. Both the anterior and intermediate femora 

 are yellowish inferiorly and posteriorly, and the posterior femora are entirely 

 yellowish, except a terminal superior and anterior black vitta. The earlets 

 are subobsolete. The 9 abdominal appendages are more than a third as 

 long as the penultimate abdominal joint, black, slender, tapering, wide apart 

 at base, acute, parallel, directed slightly downwards, twice as long as the semi- 

 circular anal process, which is yellowish, and has two black triangular vitta 

 above. The vulvar lamina is only one millimetre long, fuscous, and terminates 

 in two rather slender divaricating conical branches ; and the venter, when vi- 

 sible, has joints 3 6, and the basal two-thirds of eight fuscous. Occasionally 

 there is a very slight flavescence at the base of all four wings, Antecubitals 

 13 15; postcubitals 7 11. 



Length $ 5155 mill. 9 4856 mill. Alar expanse J" 6567 mill. 9 

 67 75 mill. Pterostigma ^ 3^ 4 mill. 9 4 4J mill. Expanse of the eighth 



1862.] 



