THE CANADIAN ENTOMOLOGIST. 105 



omitted here, being so inconstant as to be of no diagnostic value. Had 

 all the specimens of each species the typical coloration as given, recog- 

 nition by this character would be easy ; but the extent of variation is so 

 great as to render it absolutely useless. While I have not yet seen a 

 specimen of comma without the yellow suture, many specimens of pallipes 

 occur with it where the broad elytral vitta is abbreviated and disintegrated 

 so as to form a short, narrow vitta on each side. The vitta of comma is 

 similarly reduced, and the separation by color becomes impossible. In 

 other specimens of each the colors are so suffused and blended as to 

 present no typical characters. 



Ihe length of the scutellar striae, then, is the only character to be 

 relied on for separation. That of comma is said to be lo7ig ; that of 

 pallipes, short. Neglect to define the relative lengths, no doubt, gives rise 

 to the confusion where the two species do not inhabit together, and 

 material is not at hand for comparison. 



In pallipes this stria may be termed rudimentary. The examination 

 of near one hundred specimens shows it to be merely basal, and not to 

 extend notably along the plane of the elytron behind the commencement 

 of the declivity, while in comtna it is quite conspicuous, and about half a 

 line in length. 



Rugicollis is Califomian. The scutellar stria is as in pallipes. The 

 typical specimens have a short black vitta on each elytron from before the 

 middle backwards, and occupying the 2nd, 3rd and 4th striae. Specimens 

 of pallipes occur with exactly the same marking. Apart from a certain 

 microscopic rugosity of the thorax, and a little less convexity of the 

 elytral interstices, both of which may be evanescent in a large series, I 

 see nothing to distinguish them, except locality. 



Tachycellus (Brachycellus) atritiiedius. — Many individuals of this 

 species simulate in the form of the thorax and in coloration of the elytra 

 specimens of the foregoing. The scutellar stria is as in pallipes. This 

 at once distinguishes it from comma. Besides the generic character of the 

 mentum, the antennae and hind tarsi separate it from pallipes readily. 

 The three basal joints of the antennae are glabrous, and the tarsi are long 

 and narrow, the first joint being one-half longer than the second. In 

 pallipes, etc., the same tarsi are short, the joints broad and hairy. The 

 typical atrimedius has the hind angles of the thorax sharply rectangular, 

 but in many specimens they are considerably obtuse, and the four species 



