10 HYMENOPTERA OF AMERICA. [PART I. 



not in Vespoides; the fore part of the mcsothorax is also carinated, 

 but the hind part is depressed, while in Vespoides it is rather 

 elevated. The 4th and 5th joints of the antennae are quite short, 

 while in Vespoides the 4th is longer than broad. 



Hab. Rocky Mountains, Colorado Territory. 



Mr. Hidings discovered this species in August on a plant most 

 likely to be of the genus Phacelia. 



3. M, margilialis Cress. — Nigra, tenuissirne punctulata; thorace 

 quadrato, baud depresso, angulis metanoti cotupressis, hand spinosis ; 

 macula frontis, marginibus pronoti. tegularum abdomiuisque segniento- 

 rum 1-5 margine luteo; tibiis et tarsis luteis. J. 



M. marginalia Cressok, Proc. Ent. Soc. Pbilad. Ill, 1SG4, GT7, £. 



9 . The whole insect, including the head and clypeus very 

 finely punctured, coriaceous. Thorax quadrate, a little longer 

 than wide, not depressed as in M. vesjjoides, very finely punctured, 

 a little rougher along the anterior margin of mesothorax. Clypeus 

 convex, not carinated, not so much emarginate as in Vespoides. 

 Labrum triangular, with the tip truncate and rounded; its margin 

 and pubescence fuscous. The angles of metathorax not depressed, 

 but compressed, not spined. Pubescence black (or grayish, when 

 not fresh). Palpi, tip of mandibles, a line along the orbits behind 

 and on the upper part of the sinus in front, a transverse line or 2 

 spots at the insertion of the antennae, luteus. Antennas fulvous ; 

 the 1st joint and upper part of the club, blackish ; the other joint 

 rather obscure on the upper side. Border of anterior and posterior 

 edge of prothorax (more or less), and outer half of tegulae, whitish. 

 Abdominal segments 1-5 adorned above with a narrow whitish 

 band, not quite marginal, sometimes interrupted; at least the 

 first. Tibiae luteus, tarsi fulvous. Wings hyaline, with ferru- 

 ginous veins; radial cell pear-shaped, narrowly produced at its 

 inner extremity ; both recurrent veins inserted before the middle 

 of the 2d cubital cell. 



Vo.r. The bands of head and thorax replaced by mere dots; 

 clypeus with a white line ; a macula on the pleura beneath the 

 wing ; anal segment with 2 white dots ; the 3d segment beneath 

 with a row of white dots. 



Differs from M. vespoides by the finer punctuation, not rough 

 clypeus, not carinated labrum. by its forehead without carina, etc. 

 Hab. Rocky Mountains, Colorado Territory. 



