No. 3] DESCRIPTION OF CLEPSINE PLANA. 415 



understood as claiming that variation in these ways can always 

 be relied upon as an exact gauge of systematic relationship. I 

 am not unmindful that in such questions the entire organization 

 must be the final criterion in doubtful cases. Nevertheless, I 

 hold that we find in the variations above defined an important 

 guide. 



Color. — Ground - color above a dull, dark brown, with a 

 slightly darker marginal border (Figs, i and 3) encircling body 

 and disc. Along the margin there are twenty-one dull yellow 

 spots, metamerically arranged, and having the same width as 

 the dark border. The first spot is very small and on the ocular 

 ring, the second on the second ring, the third on the two buccal 

 rings, the fourth mainly on the ninth and tenth rings. From 

 this point onward the spots mark the second and third ring of 

 each somite, except the last four (XXIII-XXVI), in which 

 they are absent. Anteriorly these spots have a triangular form 

 with the apex directed towards the median line. In the sixth 

 somite they begin to assume a V-shaped form, and this passes 

 into a U-shaped form along the middle and posterior regions. 



The median portion of the tip of the head is whitish up to 

 the eyes. With the eyes begins the median yellow vitta, con- 

 stricted at irregular intervals. This vitta runs back to the 

 fourteenth ring, and then fades into an obscure patch of brown- 

 ish yellow reaching back to the twentieth ring. The extent of 

 the vitta is quite variable, as was pointed out by Say and Verrill. 



There are two rows of yellow spots metamerically arranged, 

 marking the first ring of each somite (from VII onward), and 

 situated about midway between the margin and the median line. 

 These spots are at first small, circular, and placed just inside 

 the lateral row of sense-organs (/). From the twenty-sixth ring 

 backward, they become slightly elongated so as to reach and 

 encircle the corresponding sense-organs. All the sense-organs 

 of this row, anterior to the twenty-sixth ring, are encircled with 

 a narrow border of yellow, except the first two pairs (on 2d 

 and 5th rings). The two median rows of sense-organs are 

 not thus marked, until we come to the last three pairs, which 

 have quite conspicuous borders. The outer lateral sense-organs 

 {ol) are so marked only as far as the seventeenth ring. 



Between the two rows of yellow spots there are other yellow 

 spots, scattered irregularly along the dorsal surface, varying in 



