NORTH AMERICAN HYMENOPTERA. 153 



very closely punctured, more coarsely so than the head ; niesopleui'aj tolerably 

 coarsely striato-punctate, the episternal sutui-e rather stronjily foveolate ; middle 

 segment finely striated, delicately so on the sides; abdomen finely punctured, the 

 second ventral with scattered punctures. Black ; mandibles exce])t tips, scape, 

 pedicellum beneath and sometimes part of the first joint, pronotum almost en- 

 tirely above, tubercles, episternum mesopleuralis in part, scutellura anteriorly, 

 two small spots, one on each side just anterior to it, metanotum, an elongato-ovate 

 spot, sometimes wanting, on each side of the middle segment posteriorly, femora 

 excejit their base and hind portion of posterior pair, tibise, tarsi except last two 

 or three joints, two spots on the first dorsal abdominal segment, frequently form- 

 ing a band, longer spots on second and third segments pointed internally, also 

 united sometimes, a band on segments 4 and 5, a spot on each side of the pygidial 

 segment and the ventral segments to a greater or less degree, bright yellow; pu- 

 bescence of front and clypeus silvery, with a slight golden tinge in some speci- 

 mens ; wings with a strong yellow tinge on basal two-thirds. Length 11-13 mm. 

 % . — Head very closely punctured ; space between eyes at base of clypeus dis- 

 tinctly greater than the width of the latter in the middle ; thorax more coarsely 

 sculptured than in the 9 > particularly the middle segment, whose upper surface 

 is rugoso-punctate, posterior face strongly punctured, the punctures interspersed 

 with a few striae, sides coarsely striated ; fore trochanters unarmed ; abdomen a 

 little more distinctly punctured than in the 9 i marked the same, but in the 

 specimens before me all the dorsal segments are banded, the two apical ones and 

 all the ventrals except the first being entirely yellow; wings yellower and pu- 

 bescence of front and clypeus golden. Length 11-12 mm. 



Colorado ; Nevada ; California ; Mt. Hood, Oregon ; Washington, 

 The 9 C'^ii o"ly be distinguished from that of chrysargiuus by its 

 richer livery and particularly by the ventral segments of abdomen 

 being maculated. The space between the eyes at base of clypeus is 

 somewhat greater in comparison to width of clypeus than in chrijs- 

 arginnx, and the form is usually more robust. The yellow on each 

 side of middle segment is j)eculiar to the species, but cannot be relied 

 on because of inconstancy. The % of this species as described by 

 Cresson is referable to that of chrnmrgmm. 



1. Group chrysarginus. 



The females of this group connot be distinguished from the de- 

 cemmaculatus group. The males differ by the flagellum having the 

 fourth joint emarginate and produced at apex beneath ; fore tarsi 

 not distinctly flattened. 



25. Crabro odyneroides Cress. 



Cnthro odyneroides Cresson, I. c, p. 481, % . 



9 . — Head scarcely narrowed posteriorly, rather strongly punctured, very 



closely so on the front, which appears finely granulated ; ocelli forming a low 



triangle, lower than in chrysarginus, the space between the hind pair distinctly 



less than that between them and the nearest eye-margin ; first joint of flagellum 



TRANS. AM. ENT. SOC. XXII. (20) JUNE, 1895. 



