E. T. Cresson's descriptions of two new Trigonalys. 351 



Descriptions of two new species of TBIGONALYS. 

 BY E. T. CRESSON. 



Trigonalys pulchellus. 



Male. — Head black, polished, finely and rather sparsely punctured, except 

 the middle of the front, which is rugose from the insertion of the antennce to 

 the ocelli ; mandibles, except tips, clypeus, broad frontal orbits, cheeks and two 

 small spots behind the ocelli, all white; palpi pale yellowish-white; antennae 

 as long as the body, moderately slender, much attenuated towards the tips, 27- 

 jointed. black, with a broad white annulus covering part of the 8th, the 9 — 13, 

 and part of the 14th joints. Thorax black, shining, densely and finely punc- 

 tured, slightly pubescent; mesothorax with two very deep longitudinal furrows, 

 slightly diverging on the scutellum, and also a shallow longitudinal furrow on 

 each side over the tegulse ; a large oblong spot on each side of the prothorax an- 

 teriorly, and the lateral posterior margins of the same, ending in a spot beneath 

 the tegulae, a sublunate spot on the disk of the mesothorax, tegulae, a spot he- 

 hind the tegulae, sides of the scutellum, post-scutellum, and a transverse spot 

 on each side of it, a large quadrate spot on each side of the metathorax, as well 

 as two spots on each extreme side of the same, parallel with the posterior coxae, 

 a large, subrhomboidal spot on each side of the pleura, between and a little 

 above the insertion of the anterior and intermediate coxse, and a rather large 

 double spot beneath the insertion of the anterior wings, all white; scutellum 

 prominent, closely punctured, and channeled down the middle; metathorax ru- 

 gose, with transverse sinuous, well-defined carina?. Wings entirely hyaline, 

 slightly iridescent, nervures fuscous; second submarginal cell narrow, more 

 than thrice longer than wide, and connected with the first discoidal cell by a 

 short petiole; third submarginal cell subquadrate. Legs fulvous; coxae and 

 trochanters white: posterior tarsi whitish. Abdomen ovate, polished, flattened ; 

 first segment with a round, black spot at base, surrounded by a fulvous circle, 

 posterior margin with a white oblique spot on each side; second segment ful- 

 vous, with a large, subquadrate, black spot on each side, and a transverse, lateral, 

 white spot at tip; remaining segments black, stained with fulvous on the sides, 

 the third, fourth and fifth segments each with a whitish lateral spot at tip ; 

 seventh segment very small ; apex of abdomen pointed, but slightly incurved; 

 venter simple, flattened, pearly-white, transversely stained with pale dusky; 

 extreme tip dusky. Length -i'i lines ; expanse of wings 9 lines. 

 Ilab.-AX^t Virginia, (Ridings. Coll. Ent. Soc. Phil.) 

 The shape of the abdomen of the specimen from which the above 

 description was taken is entirely different from that given in the gene- 

 ic description of Trlijondlyx, (Westwood, Trans. Ent. Soc. Lond. iii. p. 

 270.) since it is depressed, and scarcely to be called convex, either 

 above or beneath ; it is inserted immediately above and between the 

 posterior coxse ; the first segment is triangular, and about equal in 

 length with the second; the third as wide as the second, and a little 

 shorter; the fourth narrower and a little shorter than the third; the 

 three following segments rapidly decreasing iu size, and but slightly 

 incurved, the three together forming a triangle; seventh segment very 



